Veterinary and sanitary quality control of milk. Coursework: Veterinary and sanitary examination of milk

Ural State Academy of Veterinary Medicine

Department: Veterinary and sanitary examination

Course work

Veterinary and sanitary examination of milk

Troitsk, 2009

Introduction. 3

Veterinary and sanitary rules for milk production technology. General provisions. 4

Arrangement and equipment of premises and territory of dairy farms.. 6

Veterinary and sanitary requirements for milking cows. eleven

Primary processing, storage and transportation of milk. 12

Personal hygiene rules for farm workers .. 15

Veterinary and sanitary quality control of milk in complexes and farms. physical and chemical methods for determining the quality of milk. 17

Organoleptic study of milk. 18

Determination of the percentage of fat in milk. 21

Determination of the acidity of milk. 22

Determination of the purity of milk. 24

Checking the quality of milk pasteurization. 25

Determining the quality of milk. 26

Microbiological analysis of milk. 28

Express methods for detecting Escherichia coli and Salmonella bacteria in milk and equipment. 29

Indication in milk of staphylococci. 31

Sanitary evaluation of milk in animal diseases. 32

Prevention of mastitis in cows in dairy complexes and farms 34

List of used literature.. 41

Introduction

Importance of milk in human nutrition.

Milk is one of the most valuable food products. It contains about 200 substances vital for humans and young animals. The main ones are proteins, fat, milk sugar and mineral salts. Milk proteins contain 20 amino acids, including tryptophan, lysine, methionine, lecithin and others, which are essential. Milk contains 25 fatty acids, most of which are unsaturated, and therefore easily absorbed by the human body. Milk sugar (lactose) is only slightly fermented in the intestines and is almost completely absorbed. Mineral salts are widely represented in milk: calcium, potassium, sodium, magnesium, phosphorus, sulfur and others necessary for the normal course of basic life processes in the body,

In total, milk contains 45 mineral salts and microelements. Milk contains both fat-soluble vitamins - A, D. E, and water-soluble - C, P, B1, B2, B6, B12 and other regulating metabolism. It is very important that the numerous components of milk are in a strictly interconnected relationship, which is important in the life of the body. Pure fresh milk from a healthy cow has bacteriostatic properties. If freshly milked pure milk is cooled to 3-4 °, then it retains these properties for up to 1.5 days, and at a temperature of 10 ° - 24 hours. Lactic acid products made from milk (curdled milk, kefir, cottage cheese, etc.) are antagonists of putrefactive intestinal microflora and are indispensable as dietary products.

Meanwhile, milk, in case of violation of the sanitary conditions of milking, primary processing, storage and transportation, as well as diseases of cows, can be contaminated with pathogenic and toxicogenic microflora, which is dangerous for people and young animals.

Veterinary and sanitary rules for milk production technology. General provisions

The entire herd of dairy cows (buffaloes, camels, mares) must be under the constant supervision of a veterinarian or a paramedic and be examined for brucellosis, tuberculosis, and, if necessary, for other diseases in the optimal time using the methods provided for by the relevant regulatory documents of the Ministry of Agriculture of the Russian Federation.

In order to prevent contagious animal diseases, farm managers are obliged to ensure compliance with zootechnical and veterinary rules and the timely implementation of other measures provided for by the Veterinary Legislation of the Russian Federation.

To supply children's institutions (pioneer camps, children's dairy kitchens) directly from the farm, it is allowed to use milk obtained only from healthy animals. For this purpose, farms are allocated that are free from infectious animal diseases, which are located within a radius of no more than 25-30 km from the place of consumption of this milk, near highways and highways. Milk deliveries through other direct links are decided on the spot in agreement with the veterinary and sanitary and epidemiological services. All cows allocated for the supply of milk to children's institutions are subject to mandatory veterinary examination twice a month and examination for brucellosis and tuberculosis at least twice a year, for mastitis - 1 time per month. The results and actions taken are recorded in a log. An animal welfare certificate on the farm is submitted to the chief veterinarian of the district on a monthly basis.

In farms that are unfavorable for infectious diseases of cattle, measures are taken to ensure the complete recovery of the herd from these diseases in a short time. Until the elimination of the disease, when deciding on the use of milk for food and its release from the farm, one should be guided by the instructions set out in paragraphs 1.5-1.10 of these Rules and the corresponding instructions for combating infectious diseases.

If a livestock disease is suspected, the farm manager or foreman is obliged to immediately isolate the diseased animals and inform the veterinary specialist serving the farm about this.

Milk from sick cows must be drained into a separate bowl. It is forbidden to use this milk for food or animal feed and to hand it over to milk processing enterprises until a diagnosis of the disease is established.

In case of livestock disease with contagious diseases transmitted from animals to humans, veterinarians are obliged to prohibit the export of milk from the farm, its use on the farm until the diagnosis is clarified and require the implementation of measures in accordance with existing instructions for combating these diseases, at the same time inform the territorial sanitary and epidemiological service .

It is forbidden to use for food and feed to animals milk from cows suffering from anthrax, emphysematous carbuncle, rabies, malignant edema, leptospirosis, plague, general pneumonia, Q fever, as well as if the udder is affected by actinomycosis, necrobacteriosis, and in other cases provided for instructions. Such milk after boiling for 30 minutes must be destroyed.

Milk from cows suffering from or suspected of tuberculosis, brucellosis and leukemia is used in accordance with the current instructions on measures for the prevention and elimination of animal tuberculosis, on measures for the prevention and elimination of animal brucellosis, on measures to combat bovine leukemia.

Milk from the affected quarters of the udder of animals with mastitis must be destroyed after boiling. Milk from unaffected quarters of the udder of the same animals is subjected to thermal disinfection (boiling or pasteurization for 20 seconds at 76 ° C) and used to feed young farm animals.

Milk from cows treated with antibiotics should be used in accordance with current guidelines for the control of bovine mastitis.

To identify animals with mastitis, all cows on the farm must be clinically examined daily during milking and, once a month, milk samples should be examined from each udder share in accordance with current recommendations for combating mastitis in cows or from the milk yield of each cow in accordance with the current instruction on the use of a 10% solution of mastidine. The results are presented to the chief veterinarian of the district on a monthly basis.

Cow's milk delivered by farms in all respects must meet the requirements of GOST 13264-70 "Cow's milk. Requirements for procurement."

It is forbidden to donate milk obtained from cows during the first 7 days after calving and for the same period until the end of lactation. It is used for fattening young animals.

Milk, dairy products, containers of individual farms must meet the requirements set forth in the current rules for the veterinary and sanitary examination of milk and dairy products in the markets.

Arrangement and equipment of premises and territory of dairy farms

The construction of new and reconstruction (refurbishment) of existing cowsheds, dairy, milking, maternity departments, calves and other premises of a dairy farm should be carried out in accordance with the all-Union standards for the technological design of cattle enterprises (ONTP 1-77) (M. 1979) and all-Union standards technological design of veterinary facilities for livestock, fur and poultry enterprises (ONTP 8-85) (M., 1986) in compliance with the sanitary requirements provided for in them. Dairy utensils must be made from materials approved by the Ministry of Health of the Russian Federation for these purposes.

A mandatory facility on each livestock farm is a sanitary checkpoint built according to a standard design.

To receive and store milk on the farm, it is planned to build a dairy (an isolated room in a barn or a separate building) with rooms for primary processing and temporary storage of milk, for sanitizing milking equipment, storing and preparing detergents and disinfectants. In the dairy, a separate room is provided for the study of milk (laboratory).

To ensure the proper sanitary condition of livestock and milking premises, it is necessary to constantly monitor their cleanliness, landscaping of the territory of farms, walking areas, entrances to cowsheds, calves, milking rooms and dairy.

The farm should be surrounded by a fence and a strip of green spaces. The territory free from buildings is also landscaped and landscaped.

Ministry of Agriculture and Food of the Russian Federation

Ural State Agricultural Academy

Course work

according to "Veterinary and sanitary examination"

Topic: Veterinary and sanitary examination of milk in the SHPK "Pervouralsky", department No. 1.

Performed:

Abdulkhakova S. G.

FVM gr. 534

Checked:

Petunina A. G.

Ekaterinburg

General information about the economy…………………………………….

The concept of veterinary and sanitary examination……………..

Chemical composition and nutritional value………………………..

Organoleptic properties…………………………………….

Physical and chemical indicators…………….………………….

Bacteriological indicators…………………………………

Research of milk in SHPK "Pervouralsky"……………

Conclusions…………………………………………………………….

Bibliography…………………………………………….....

Application………………………………………………………..

SHPK "Pervouralsky"

General information about the economy:

The state farm "Pervouralsky" was organized on March 1, 1961 on the lands of two subsidiary farms of the Novo Pipe and Staro Pipe Plants, and a number of small farms in the Pervouralsky district of the Sverdlovsk region.

Dairy farming in SHPK "Pervouralsky" is the leading industry. As of 01.01.07, the farm has 2,136 head of cattle, including 870 cows. For the last 5 years SHPK "Pervouralsky" has been working steadily in the field of dairy farming. Breeding farm "Pervouralsky" is a reproducer of a new type of Ural black-and-white cattle.

The dairy shop for the production of packaged pasteurized milk is located on a commercial dairy farm. Packaged milk is sold in Pervouralsk, the rest of the milk is delivered to dairy plants: Urallat LLC, Khladokombinat No. 3 LLC, Revdinsky Dairy Plant CJSC.

The concept of veterinary and sanitary examination:

Veterinary and sanitary examination is one of the branches of veterinary medicine that studies the methods of sanitary and hygienic examination of food products and technical raw materials of animal origin and determines the rules for their veterinary and sanitary assessment. animal husbandry. A veterinarian should be able to carry out veterinary and sanitary measures and solve issues of sanitary and hygienic research and veterinary and sanitary well-being of food products and technical raw materials of animal origin during their production (collective farms, state farms, poultry farms, agro-industrial and livestock complexes, cooperative organizations, etc.). ), at all stages of processing technology (meat, milk, poultry plants and other enterprises), during transportation, storage, as well as in places of sale (markets). Taking into account these requirements, the veterinarian must have practical skills in receiving and handing over slaughter animals, transporting and preparing them for slaughter, know the basics of technology and standardization in the production of livestock products, possess modern methods of their research and knowledge of scientifically based sanitary assessment.

Veterinary and sanitary examination is a science that studies the methods of sanitary and hygienic examination of food (meat, milk, fish, eggs) and raw materials (leather, wool, etc.) products of animal origin, as well as establishing a scientifically based veterinary and sanitary assessment of these products.

Knowledge of veterinary and sanitary expertise is of great importance in

training of the future veterinarian.

In practical work, the veterinarian is constantly faced with

issues of veterinary sanitary examination at meat processing plants, in transport, in

laboratories, on collective farm markets in urban and rural areas, in

collective farms and state farms, in fisheries, etc. Therefore, the veterinarian must have a good command of the complex of sanitary and hygienic studies of livestock products. Only in this case, he will be able to properly organize the examination of products and give a reasonable conclusion about their sanitary condition and about the most rational ways to use low-quality products and raw materials.

The main thing in the work of a veterinary and sanitary expert is to prevent

the possibility of infecting people through products obtained from sick animals, as well as to prevent the transfer of infectious diseases from infected products (raw materials) to healthy animals. At the same time, anthropozoonoses, diseases common to animals and humans (anthrax, tuberculosis, brucellosis, trichinosis, and others) pose a particular danger.

The veterinarian, as State Comptroller, is obliged to allow only good-quality products to be eaten.

Poor-quality (infected) products and waste from slaughterhouse production, at the direction of a veterinarian, are confiscated and must be neutralized or destroyed.

The main objects of study of the veterinary and sanitary examination are food products and raw materials obtained from the slaughter of farm animals, as well as milk and dairy products, fish, eggs, vegetable products and bee honey.

The main purpose of the veterinary and sanitary examination:

1) protect people from diseases that can be transmitted through

meat and dairy, fish and egg products, animal raw materials;

2) ensure high sanitary quality of products and raw materials

of animal origin during their primary processing,

storage and transportation;

3) control the quality of the products sold on the market

products;

4) prevent spread through animal products

infectious and parasitic diseases.

Chemical composition and nutritional value:

MILK- a complete and healthy food product. It contains all the nutrients necessary for life, needed to build the body. The natural purpose of milk in nature is to provide nutrition to the young organism after birth. The composition of the milk of various mammals is generally determined by the environmental conditions in which the growth of a young organism occurs. This is especially clearly manifested in the content of protein and fat, the more of them in the mother's milk, the faster her child grows.

So, an infant doubles its weight in about 180 days, a calf in 50 days, and a puppy in 9 days. The protein content in women's milk, compared with the milk of various animals, is the lowest - 1.6%, in cow's milk - 3.4%, and in dog's milk - 7.3% of protein. Milk fat serves primarily to meet the body's need for energy. In areas with a cold climate, the body's need for energy is higher than in areas with a temperate climate. That is why the milk of the female reindeer has a higher fat content - 19.7%. Milk has survived many civilizations before it became a food product and has its own purpose:

As a food product for the population,

Means for feeding young animals and feed in animal husbandry,

Raw materials for food production,

The source of obtaining individual components of milk, which, in turn, serve as raw materials for pharmacology and other industries.

The ever-increasing importance of milk as a complete food product and as a raw material has led to an increase in demand for it. As a result, milk production has become one of the most important branches of agricultural production. At present, milk makes up a significant share in the gross agricultural product of our country.

The nutritional value of 1 liter of milk is 685 kcal. Calorie content depends mainly on the content of fat, protein. Due to the content of the most important nutrients in milk, mainly protein, carbohydrates, vitamins, minerals, it is also a protective factor. In order to protect health in enterprises where there are harmful working conditions, workers receive milk.

Milk protein is an important protective factor, since, due to its alephoteric nature, it binds pairs of acids and alkalis, and also neutralizes toxic heavy metals (traces) and other substances harmful to health. Due to the content of calcium, phosphorus, and vitamins in milk, the development of beriberi is prevented. In addition to human nutrition, milk is used to feed farm animals: calves, pigs, birds.

The chemical composition of milk is as follows: proteins 3.5%, fats 3.4%, milk sugar 4.6%, mineral salts (ash) 0.75%, water 87.8%. The chemical composition of milk varies depending on the breed of animals, the season, the nature of the feed, the age of the animals, the lactation period, and the technology of milk processing.

Milk proteins are readily available for digestive enzymes, and casein has a unique property, forming a glycopolymacropeptide in the process of digestion, to have a regulatory effect on increasing the digestibility of other nutrients.

Milk proteins are represented by casein, albumin and globulin. They are complete and contain all the amino acids necessary for the body. Casein in milk is in the form of caseinogen in a bound state with calcium. When milk souring, calcium is split off from casein, which, coagulating, precipitates.

Milk fat in milk is in the form of tiny fat globules 0.1-10 microns in size. When milk is standing, fat globules rise up due to their low specific gravity, forming a layer of cream. Due to the low melting point (within 28-36 ° C) and high dispersion, milk fat is absorbed by 94-96%. As a rule, the fat content of milk in autumn, winter and spring is higher than in summer. It also increases towards the end of the lactation period. In this case, the conditions of keeping the animal and the nature of the feed are of great importance. With good care, the amount of fat in milk can reach 6-7%.

Carbohydrates in milk are in the form of milk sugar - lactose, which is less sweet in taste than vegetable sugar, but its nutritional value is not inferior to it. When boiled, milk sugar caramelizes, giving the milk a brownish color and a specific aroma and taste. Milk sugar is of great importance in the production of lactic acid products. Under the action of lactic acid bacteria, it turns into lactic acid; while curdling the casein. This process is observed in the production of sour cream, curdled milk, cottage cheese, kefir. The composition of milk includes phosphorus, calcium, potassium, sodium, iron, sulfur. They are found in milk in an easily digestible form, which is especially important in early childhood, when milk is the staple food. Of the trace elements in milk contains zinc, copper, iodine, fluorine, manganese.

The main vitamins of milk are vitamins A and D, some amounts of ascorbic acid, thiamine, riboflavin, nicotinic acid. Their content is subject to significant fluctuations. In summer, when animals eat juicy green fodder, the content of vitamins in milk increases. In winter, due to the transition to dry food, the amount of vitamins in milk decreases. In the future, the content of vitamins depends on the conditions of storage, transportation and processing of milk. The average content of ascorbic acid in milk is 6.6-18.9 mg, thiamine 370-485 mcg, nicotinic acid 1500 mcg, riboflavin 952-1580 mcg, vitamin A 0.1-0.35 mg, carotene 0.08-0 .23 mg per 1 liter. The calorie content of milk is low and averages 65-66 kcal per 100 g of product.

Milk contains a number of enzymes. The main ones are: phosphatase, peroxidase, reductase, amylase, lipase and catalase.

Organoleptic properties:

Fresh high-quality milk supplied for direct consumption, in accordance with GOST 13277-67, must be homogeneous, have a white color with a slightly yellowish tinge, a pleasant smell and taste, and a liquid consistency. Changes in color may be due to the nature of the feed, the development of certain pigment-forming microbes in milk, and animal diseases. So, blue-blue coloration of milk can be caused by the consumption of feed containing blue pigments, when milk is stored in zinc dishes, with mastitis and tuberculosis of animals, or due to the development of Pseudomonas aeruginosa, B. piocianeum, in milk. The yellow color of milk may be due to the multiplication of microbes that produce yellow pigment, with mastitis, eating certain herbs (bison, rhubarb). A reddish coloration of milk almost always indicates an admixture of blood.

A foreign smell in milk very often appears when it is stored with substances that have pungent odors (fish, tobacco, kerosene, gasoline). With a long standing in the barnyard, the milk acquires the smell of manure, when stored in rotten wooden cellars - a musty smell.

Keeping animals on certain feeds (with an admixture of wormwood, onions, field mustard, rutabaga, etc.) often causes a change in the taste of milk. Changes in smell and taste can be caused by drugs administered to animals for the purpose of treatment. Due to the development of B. lactis viscosum and Str. Gunteri, it can acquire a slimy, viscous texture.

As a rule, milk with an unusual color; unpleasant fodder odor and taste, with a changed consistency in food is not allowed. It can only be used for animal feed.

Physical and chemical indicators:

Currently, the dairy industry produces a diverse range of milk: whole normalized or reconstituted, with high fat content and non-fat, baked, protein, fortified. Diverse and packaging milk. It is available in bottles and paper bags (tetrapacks), flasks and tanks. In this regard, indicators of the qualitative state of milk for different types of milk are not the same. The main physical and chemical indicators characterizing the freshness and naturalness of milk are indicators of specific gravity, acidity, fat content and dry residue.

The relative density (specific gravity) of milk ranges from 1.029-1.034, which depends on its chemical composition. When diluted with water, the specific gravity of milk decreases, when cream is removed or impurities (soda, starch) are added, on the contrary, it increases.

The acidity of milk is expressed in Turner degrees. Turner's degree is the number of milliliters of 0.1 N alkali solution needed to neutralize acids in 100 ml of milk.

The acidity of fresh, freshly milked milk is due to the presence of phosphate, citrate salts and proteins. During storage, due to the development of lactic acid microflora, the acidity of milk increases due to the formation of lactic acid from sugar. At high acidity, milk acquires an unpleasant sour taste and coagulates when boiled. Coagulation of milk when heated can occur already at its acidity of 25-27 °T. At 30 °T, milk coagulates without heating. In this case, milk casein precipitates in the form of clots, separating from the liquid part - whey.

PH for raw milk is a quality indicator, and for dairy products it is a quality indicator and a process control factor.

PH - as an indicator of quality. It is established quite clearly, however, the use of pH as a quality indicator is not yet fully provided for by the national standards of individual countries. On a global scale, there is a trend towards including the pH of dairy products, mainly rennet cheeses, in their quality assessment. Dairy products of satisfactory quality are characterized by a certain pH value, for example, whole milk - 6.6 - 6.8; condensed - 6.1 - 6.4; yoghurts - 4.0 - 4.3; curd whey - 4.3 - 4.6, etc.

According to the pH value, one can judge the ability of milk to coagulate:

mastitis milk - 6.8;

normal fresh - 6.6 - 6.8;

beginning to turn sour - 6.3;

coagulation upon heating - 5.7;

coagulation with the formation of a clot - 5.3 - 5.5.

The pH value changes with sudden temperature fluctuations, and the temperature change causes the pH to deviate into the acidic zone. A sudden increase in temperature leads to a deviation of the pH into the alkaline zone.

The osmotic pressure of milk, like other physiological fluids of animals, is maintained at a constant level. Therefore, with an increase in the content of chlorides in milk as a result of a change in the physiological state of the animal, especially before the end of lactation or in case of illness, there is a simultaneous decrease in the amount of another low molecular weight component of milk - lactose.

The freezing point is also a constant physical and chemical property of milk, since it is determined only by the truly soluble constituents of milk: lactose and salts, the latter being contained in a constant concentration. The freezing temperature fluctuates within narrow limits from -0.51 to -0.59°C. It changes during the lactation period when the animal becomes ill and when milk, water or soda is adulterated. And due to the deviation of the increment of lactose. At the beginning of lactation, the freezing temperature decreases (-0.564 ° C), in the middle it rises (-0.55 ° C); at the end it decreases (-0.581°C).

Bacteriological indicators:

Freshly milked milk is not a sterile product, since there is always a certain amount of microbes in the cavity of the individual mammary glands of the udder and especially in the teat canal. These microbes, mainly micrococci, together with mucus, can clog the teat canals in the form of plugs, which are pushed out with the first streams of milk during milking. Freshly milked milk also contains some lactic acid bacteria Streptococcus lactus, Bact casei. These microorganisms further ferment the milk sugar to form lactic acid, which increases the acidity of the milk and causes it to turn sour.

Milk is a nutrient medium for microorganisms that enter it already during milking from the udder, hands, dishes, air, etc. Once in milk, these microorganisms multiply rapidly, especially if the milk is stored at elevated temperatures and the bactericidal period in it has ended . Their number after a short time (1-2 days) can increase to hundreds of millions in 1 ml.

The development of putrefactive microflora (B. proteus, B. subtilis, B. putrificus, B. fluoroscens) causes rotting of milk proteins, which worsens the taste: an unpleasant taste and smell appear. Along with the specified microflora, milk may also contain pathogenic microorganisms - causative agents of intestinal infections (dysentery, typhoid fever), which can get from bacillus excretors along the entire route of milk to the consumer. Milk, in addition, can be infected by the animal itself when it becomes ill with tuberculosis, brucellosis, foot and mouth disease, mastitis. The content in milk of Mycobacterium tuberculosis, brucellosis bacilli, staphylococci or foot-and-mouth disease viruses from animals with a clinically pronounced picture of the disease can be especially significant. In smaller quantities, they are found in the milk of animals that do not have obvious clinical manifestations.

Due to the fact that milk obtained from sick animals or contaminated with microorganisms, pathogens of intestinal infections, can serve as a source of human infection with tuberculosis, brucellosis, etc., according to existing sanitary rules should be used after decontamination. At the same time, the neutralization of milk from animals with a pronounced clinical picture of the disease should be carried out most carefully. Thus, milk from animals with severe symptoms of brucellosis or from animals in farms quarantined for foot-and-mouth disease can be used inside the farm only after boiling for 5 minutes from the moment of boiling. The export of milk from such farms, even neutralized, is allowed only after agreement with the authorities of the anti-epidemic service and veterinary and sanitary supervision. Milk from animals with a pronounced clinical picture of tuberculosis is not allowed for use in food.

Milk from animals with positive reactions to tuberculosis and brucellosis can be sold after pasteurization at a temperature of 70 °C for 30 minutes or at least 90 °C for several seconds. At the same time, milk received by the dairy from brucellosis farms must be re-pasteurized in the usual manner.

Research of milk in SHPK "Pervouralsky":

First of all, an organoleptic study of milk is carried out - the color, taste, smell, texture of milk and the presence of defects are established.

The color is established visually, the smell is sensory, the consistency is transfused, and the presence of defects is a complex of these signs.

In SHPK "Pervouralsky" a milk analyzer - KLEVER-1M is used to study milk.

The milk analyzer "KLEVER-1M 220" is registered in the State Register of Measuring Instruments of the Russian Federation under No. 15274-01.

Purpose of the milk analyzer KLEVER-1M:

The device provides an express assessment of the percentage of fat, dry skimmed milk residue (SOMO) and density in a single sample of fresh whole, canned milk or cream. The measurement technique is based on the change in the parameters of ultrasound in milk depending on the temperature and composition of the milk. Without the use of chemical reagents, the device allows you to simultaneously measure the content of the mass fraction of fat, SOMO, density, temperature.

Basic information and technical characteristics of clover - 1M:

Measurement range:

Mass fraction of fat, %: 0...20

Mass fraction of protein, %: 2...4

Mass fraction of SOMO, %: 6...12

Density, kg/m3: 1000 - 1040

Mass fraction of added water, %: 1 - 100 (1)

Temperature, 0С: 5 - 30

Supply voltage: 250 V

Dimensions: 257x132x108mm

Weight: 1 kg

Warranty period: 2 years

The principle of operation of the KLEVER-1M Milk Analyzer is to fill in the sample for measurement and drain it after measurement. The device comes with graduations for cow's milk and cream. Recorded calibrations are stored in the internal memory of the device for an unlimited time. The device has free graduations. They make it possible, upon a separate order of the consumer, to record additional graduations, for example, for measuring goat or sheep milk.

The analyzer "KLEVER-1M" works autonomously, but can be connected to an IBM/PC computer for calibration or registration of measurement results. RS 232 interface for connecting to a computer. To operate the analyzer with a computer, everything necessary for connection is supplied with it, including a cable and software for Windows.

Main parameters:

the volume of the analyzed sample - 20 cm3;

productivity - 22 samples/hour;

analysis time - 2.5...3.5 min.

In SHPK "Pervouralsky" 2 times a month control milkings are carried out, as a result of which milk from each cow is analyzed through a milk analyzer - Klever - 1M. The results are recorded in a special ledger.

Milking cows with milking machines. Before putting on the teat cups, one or two streams of milk from each teat must be milked into a special mug with a dark inner surface. If small flakes, an admixture of blood, mucus are found in the first streams of milk in a cow, or there are redness, compaction, swelling on the surface of the udder and teats, then such a cow should be treated and milked manually until complete recovery. Milk from cows with diseased udders after boiling is used on the farm to feed young animals. If there are no changes in the udder, those cows are milked by the machine. The duration of preparatory operations from washing the udder to putting on the teat cups should not exceed 1 minute. At the end of milking, when the flow of milk into the machine stops, it is necessary to milk the cow, for this the milkmaid slightly pulls the machine down and forward by the collector with one hand, and with the other hand at this time holds the masses of the udder. This technique facilitates the milking of the last portions of the most fat milk.

A very important element in the task of improving the quality of milk is the control by veterinarians of the health status of the udders of cows in groups of milkmaids and in the whole herd. For this purpose, monthly monitoring of the content of somatic cells in milk is carried out, which should be determined along with the content of milk fat and protein in a specialized laboratory. When the content of somatic cells in milk is more than 500 thousand/ml, it is necessary to examine the cow by a veterinarian to determine the cause of the increase in the content of somatic cells.

During the milking process, milk is collected through milk pipelines into one common container, where it is cooled. Then every day, at 12 noon, milk from department No. 1 is delivered to the dairies of the Sverdlovsk region. Every day a milk truck arrives, into which milk is pumped, by means of a hose drawn from the milk to the tank of the milk truck. After refueling the milk tanker, a control sample of milk is taken - already from the machine, as in the case of control milking, the sample is checked using the Klever-1M milk analyzer. Fresh raw milk is characterized by certain organoleptic properties (indicators): appearance, texture, color, taste and smell. In accordance with GOST "Cow's milk, procurement requirements", milk should be a homogeneous liquid without sediments and flakes, from white to slightly yellow in color, without foreign tastes and odors. The white color and opacity (turbidity) of milk cause colloidal protein particles and fat globules that scatter light, a yellowish tint is fat-soluble carotene, a mild (sweet) taste inherent only in milk - lactose, chlorides, fatty acids, as well as fat and proteins. Pleasant subtle scent raw milk depends on the presence in it of a small amount of dimethyl sulfate, acetone, volatile fats, acids, acetaldehyde, and other carbonyl compounds. The amount of chlorides in milk depends on the state of health of the animals and art. lactation, the content of dimethyl sulfide - on the type of feed fed, acetone - on feeding regimes and the state of health of animals, fatty acids on the degree of fat hydrolysis. A pronounced taste and smell in milk is considered abnormal.

A veterinary certificate and an invoice are drawn up by a veterinarian for the milk being sent.

Ural State Academy of Veterinary Medicine

Department: Veterinary and sanitary examination

Course work

Veterinary and sanitary examination of milk

Troitsk, 2009

Introduction. 3

Veterinary and sanitary rules for milk production technology. General provisions. 4

Arrangement and equipment of premises and territory of dairy farms.. 6

Veterinary and sanitary requirements for milking cows. eleven

Primary processing, storage and transportation of milk. 12

Personal hygiene rules for farm workers .. 15

Veterinary and sanitary quality control of milk in complexes and farms. physical and chemical methods for determining the quality of milk. 17

Organoleptic study of milk. 18

Determination of the percentage of fat in milk. 21

Determination of the acidity of milk. 22

Determination of the purity of milk. 24

Checking the quality of milk pasteurization. 25

Determining the quality of milk. 26

Microbiological analysis of milk. 28

Express methods for detecting Escherichia coli and Salmonella bacteria in milk and equipment. 29

Indication in milk of staphylococci. 31

Sanitary evaluation of milk in animal diseases. 32

Prevention of mastitis in cows in dairy complexes and farms 34

List of used literature.. 41

Introduction

Importance of milk in human nutrition.

Veterinary and sanitary rules for milk production technology. General provisions

If a livestock disease is suspected, the farm manager or foreman is obliged to immediately isolate the diseased animals and inform the veterinary specialist serving the farm about this.

Milk from cows treated with antibiotics should be used in accordance with current guidelines for the control of bovine mastitis.

Cow's milk delivered by farms in all respects must meet the requirements of GOST 13264-70 "Cow's milk. Requirements for procurement."

It is forbidden to donate milk obtained from cows during the first 7 days after calving and for the same period until the end of lactation. It is used for fattening young animals.

Milk, dairy products, containers of individual farms must meet the requirements set forth in the current rules for the veterinary and sanitary examination of milk and dairy products in the markets.

Arrangement and equipment of premises and territory of dairy farms

A mandatory facility on each livestock farm is a sanitary checkpoint built according to a standard design.

The farm should be surrounded by a fence and a strip of green spaces. The territory free from buildings is also landscaped and landscaped.

At the entrance to the vestibules of cowsheds and other industrial premises for the disinfection of shoes, disinfection cuvettes are equipped (baths with a disinfectant solution, straw mats, boxes with sawdust or finely chopped straw, etc.), which are systematically filled with a disinfectant solution.

On each farm, a manure storage facility is built according to an approved standard design in accordance with the all-Union norms for the technological design of systems for the removal, processing, disinfection, storage, preparation and use of manure and manure (ONTP 17-85) (M. 1983). Treatment facilities and near-farm manure storage facilities should be arranged on the leeward side in relation to the farm, as well as settlements, no closer than 60 m from livestock buildings and 100 m from dairy blocks.

The territory of the treatment facilities should be fenced, landscaped with fast-growing trees and shrubs, landscaped and have driveways and a paved access road.

The installation of treatment facilities for farms should be completed before the commissioning of livestock enterprises.

Barn slurry removal systems should ensure timely removal of excreta, maximum cleanliness of livestock buildings with minimal clean water, money and labor costs.

Each dairy farm should have one of the methods for decontaminating liquid manure: long-term, chemical or biological. Manure from farms that are unfavorable for tuberculosis and brucellosis is disinfected in accordance with the current recommendations for the disinfection of manure in farms that are unfavorable for tuberculosis and brucellosis.

Yard toilets (in the absence of sanitary facilities in amenity premises) and cesspools on the territory of the farm are allowed to be arranged at a distance of no closer than 25 m from cowsheds and other premises of the farm.

When filling cesspools and toilets two-thirds of the depth, they are cleaned. Disinfection and discharge of sewage is carried out in accordance with the current rules for the protection of surface water from pollution by sewage.

It is necessary to monitor the parameters of the microclimate in the premises for animals. Microclimate parameters are provided in accordance with ONTP-1-77.

To cool milk on the farm, special refrigeration units are equipped. In their absence, a glacier is needed with a reserve of ice at the rate of 1 m3 per 1 ton of milk. The place of ice harvesting is determined in agreement with the territorial sanitary and epidemiological service. Harvesting or freezing of ice from polluted reservoirs is not allowed.

In the dairy, laboratory, disinfectant storage room and milking parlor, wall panels are painted with light-colored oil paint or tiled with tiles or polymeric materials, and the upper part of the walls is painted with oil paint.

Summer camps provide enough cold and hot water of drinking quality, detergents and disinfectants, filter materials, washstands, benches for milkmaids, etc.

For household and technological purposes (sanitary treatment of milking equipment and milk utensils, washing of the udder, etc.), the farm must be provided with drinking quality water in accordance with GOST 2874-82. "Drinking water. Hygienic requirements and quality control".

VETERINARY AND SANITARY REQUIREMENTS FOR MAINTENANCE OF PREMISES, TERRITORIES OF FARMS AND CARE OF ANIMALS

To ensure and maintain the proper sanitary condition of livestock buildings and the territory of dairy farms, it is necessary to constantly monitor their cleanliness and landscaping.

At least once a month, spend a sanitary day on the farm. On this day, walls, feeders, drinking bowls and other equipment are thoroughly cleaned, as well as windows in industrial, domestic and auxiliary premises, and a sanitary inspection room. After mechanical cleaning, disinfection is carried out;

feeders, contaminated places of walls, partitions and pillars are whitened with a suspension of freshly slaked lime. On this day, the veterinary staff examines all dairy animals, paying special attention to the condition of the udder, teats, and checks the quality of sanitary cleaning of the premises and territory. The results of the inspection and verification are recorded in a journal, a farm passport, which are kept by the farm manager.

Entrance to the internal territory of the farm is allowed only through sanitary checkpoints for service personnel with the presentation of permanent passes, and for other persons with one-time passes issued in agreement with the veterinary service. Visits to the farm by unauthorized persons are recorded in a log kept together with passes at the control point of the sanitary checkpoint.

Entrance to the farm is allowed only after changing your own clothes and shoes in the sanitary inspection room for work clothes.

Entry of vehicles to the farm is allowed only through disinfection barriers.

Throughout the territory, in the production and utility rooms of dairy farms, preventive disinfection and measures to combat flies and rodents are carried out in accordance with the current instructions for disinfection, disinfestation, deratization and desacarization.

In the dairy and milking parlor, the walls are systematically (as far as they become dirty) cleaned and whitewashed with a suspension of freshly slaked lime. The floors are washed daily. The premises are disinfected twice a month with a solution of calcium (sodium) hypochloride containing 3% active chlorine. The consumption of the solution is 0.5 l per 1 m2 of area. Exposure 1 hour

In summer, pasture, stall-camp and stall-walking systems for keeping animals are used, and in winter-stall - tethered and loose.

Specialists choose the most appropriate of them taking into account the specific conditions of the economy (security of feed, quality of the herd, veterinary well-being, qualifications of personnel, etc.).

Dairy cows in loose housing should be provided daily with clean straw or other bedding at the rate of 5 kg per cow.

When cows are kept in stalls, bedding (straw, sawdust, etc.) is replaced daily.

It is forbidden to use peat fluff as bedding for dairy cows.

Cleaning the skin and washing the hind limbs of cows is carried out by milkmaids as they get dirty.

It is forbidden to introduce animals into the farm from other farms or farms without the permission of a veterinarian and compliance with these rules.

Veterinary and sanitary requirements for milking cows

When organizing machine milking, they are guided by the "Rules for machine milking of cows" (M., 1984).

Operators of machine milking are obliged to strictly comply with the sanitary rules for milking cows, keep the milking rooms clean, and constantly monitor the condition of the udders of animals.

Cows are milked at a strictly defined time, provided for by the daily routine on the farm. The milkmaid (machine milking operator) before milking must: wash warm water with soapy hands and wipe them with a clean individual towel, then put on a clean overalls or dressing gown and a scarf; using a spray gun (nozzle) or a marked bucket specially allocated for this purpose, carry out pre-milking treatment of the udder, while replacing the water in the bucket as necessary, after rinsing the dishes; dry the udder with clean individual napkins. In the absence of them, 2-4 towels are used. To dry the udder, the towel is pre-rinsed in water and wrung out.

To detect signs of mastitis in cows, before putting on milking cups or during manual milking, several streams of milk are put into a special mug from each nipple, which must be destroyed. It is unacceptable to milk the first streams of milk on the floor, as the secret from sick cows contains pathogenic microorganisms and can cause the spread of mastitis.

In case of excretion of curdled clots, blood or pus with milk, as well as if redness, swelling, soreness of the udder is detected, immediately inform the veterinarian (paramedic) about this, and drain the milk into a separate labeled container. At the end of milking such a cow, the operator must thoroughly wash his hands and disinfect them, and sanitize the milking equipment and utensils into which this milk was poured in accordance with the current sanitary rules for caring for milking machines and milk utensils, monitoring their sanitary condition and the sanitary quality of milk .

Immediately before manual milking of cows, the pails are washed with warm water (30 ± 5 ° C). The use of the pail for other purposes (watering calves, storing skid milk, washing, etc.) is prohibited.

Milking should be done with dry hands until the milk flow stops completely, then massage the udder and finish milking the last portions of milk. Then wipe the nipples dry with a clean towel and grease with a special disinfectant (antiseptic) emulsion.

Primary processing, storage and transportation of milk

The primary processing of milk is carried out in the dairy. The milk obtained during milking is filtered through a strainer with a cotton filter or a filter made of non-woven fabric. To filter milk, white flannel, waffle or lavsan fabric is used.

A cotton or non-woven fabric filter is used to strain one flask of milk, after which it is replaced with a new one.

Fabric filters, as they become contaminated with mechanical impurities, are rinsed in running water.

In the absence of the above filter materials on the farm, gauze is used.

Milk is filtered through gauze in 4-6 layers, fabric (including lavsan) filters in two layers.

After straining the milk of the entire milk yield, the cotton fabric filters are washed in a 0.5% warm solution of desmol or washing powder, rinsed in running water, ironed or boiled for 12-15 minutes and dried. Lavsan fabric filters after washing in a detergent solution are immersed for 20 minutes in a freshly prepared 1% sodium hypochlorite solution or a clarified bleach solution containing 0.25-0.5% active chlorine, rinsed with water and dried.

The consumption rates of filter materials based on the amount of milk produced are given in the appendix.

With the centralized export of milk, it is provided for its cooling and temporary storage on the farm for 12-24 hours, followed by export by specialized transport according to the established schedule. The farm should have enough containers for separate storage of morning and evening milk.

Milk is cooled to 4-6°C. The temperature of milk upon acceptance at the dairy plant should not exceed 10 °C.

When machine milking into a milk line, the milk must be cooled immediately in the flow. When milking in portable buckets, the time interval between milking and the beginning of its cooling should not exceed 16-20 minutes.

The duration of storage of milk depends on its temperature (see table).

The shelf life of milk various temperatures cooling

After each milking, before being taken out of the farm, the milk is cooled, guided by the basic requirements set out in paragraph 5.2. In addition to milk coolers, you can use ice pools in which flasks of milk are immersed. The milk level in the flasks must be below the water level in the cooling container. At the same time, the lids of the flasks should be open, and the entire pool with flasks should be covered with clean gauze. To ensure uniform cooling of milk, it is periodically (after 20-30 minutes) mixed with a clean whorl.

By agreement with the enterprises of the dairy industry and other producers, the state veterinary and sanitary supervision bodies, it is allowed to deliver milk without cooling within 1 hour after milking. At the same time, the farm must guarantee the high sanitary quality of the delivered milk.

To supply children's institutions, only chilled milk of at least grade I according to GOST 13264-70 is allowed, delivered no later than 12 hours after receiving it on the farm.

Milk should be transported to milk collection points or dairies in tank trucks or by dedicated transport in flasks.

The bodies of vehicles transporting milk in flasks must be clean and free of foreign odors.

It is not allowed to transport milk together with strong-smelling, dusty and poisonous substances (gasoline, kerosene, tar, pesticides, cement, chalk, etc.), as well as the use of milk tanks for transporting other substances.

Containers used to transport milk. should be hermetically sealed with lids equipped with sealing gaskets made of rubber or polymeric materials approved by the Ministry of Health of the Russian Federation for contact with food products. The use of other materials as seals is prohibited.

Tanks and flasks with milk are sealed before shipment. In summer, flasks are filled with milk to the lid (to avoid shaking and churning fat during transportation), and in winter - only to the neck.

To protect milk from heating in the summer, and from freezing in winter, the flasks are covered with a clean tarpaulin or other protective materials.

Rules for personal hygiene of farm workers

Persons employed and working on farms are required to undergo, in accordance with the current instructions for conducting mandatory preventive medical examinations of persons employed and working at food enterprises, at water supply facilities, in children's institutions, and other medical examinations (medical examination with the exclusion of brucellosis and tuberculosis from the anamnesis), x-ray studies, studies on the carriage of pathogens of intestinal infections, helminthiasis. Milkmaids are trained in hygiene according to the approved program. Additionally, medical examinations are carried out at the direction of the institutions of the sanitary and epidemiological service.

Persons who do not have documents on medical examinations are not allowed to work on dairy farms by state sanitary and veterinary supervision institutions.

Responsibility for the admission to work of persons who have not passed the necessary medical examinations lies with the farm manager or foreman.

On each farm, a sanitary post is created from among the farm workers. Employees of the sanitary post monitor the implementation of personal hygiene rules by livestock breeders, carry out preventive work to protect the health of milkmaids, daily inspect the exposed parts of the body of milkmaids for the absence of pustular diseases, monitor cleanliness and order on the farm, control the passage of preventive medical examinations by attendants. The head of the farm must have a first aid kit, a journal and personal medical books for employees.

Machine milkers and other persons who come into contact with milk should maintain personal hygiene, cut their nails short, and keep shoes and clothing clean. Take off your overalls when going to the toilet. Then wash your hands thoroughly with soap and put on protective clothing.

If you feel unwell, have a fever, suspect a disease, and if pustular skin diseases, burns, cuts appear, immediately inform the head of the farm, the sanitary post and the medical worker.

After a medical examination or treatment, present a personal medical book to the farm manager.

It is forbidden to leave the barn in overalls.

Do not stab sanitary and special clothing with pins and needles and keep foreign objects in pockets in order to prevent them from getting into milk and animal feed. Eating and smoking should only be done in designated areas.

Farm managers and foremen are required to:

to have for each employee the number of sets of special clothing established by the norms, to issue them to the employee for the duration of work and to ensure regular washing and repair. Change of special clothing as it gets dirty, but at least once every 3 days;

organize classes and examinations on hygiene according to the program by all farm workers at least once every 2 years;

ensure the purchase of personal medical books and organize regular medical examinations of farm workers;

keep a journal to record the instructions and proposals of the State Veterinary and Sanitary-Epidemiological Services.

Responsibility for the implementation of these Rules rests with the heads of farms and farm managers.

Control over the implementation of these Rules is carried out by the bodies and institutions of the state veterinary supervision and the sanitary and epidemiological service.

Those guilty of violating these Rules are held liable in accordance with the Veterinary Legislation and the current regulation on state sanitary supervision of the Russian Federation.

Veterinary and sanitary quality control of milk in complexes and farms. physico-chemical methods for determining the quality of milk

Sampling and preparing them for analysis. When sampling for research, it is very important that a proportional amount of milk is taken from each milking (average sample). The selection is made with a metal tube with a diameter of 8 - 10 mm after thorough mixing of milk in each flask. Before sampling, milk in tanks is mixed with a whorl for 3-4 minutes, and samples are taken from each section of the tank. The layer of cream adhering to the walls of the flask is cleaned and mixed with milk. Before sampling, the tube is rinsed with the same milk from the test flask. The collected samples are poured into a flask.

For a complete production analysis, 250 ml of milk is required. If necessary, milk samples for some studies can be preserved by adding 1 ml of a 10% solution of potassium dichromate for every 100 ml of milk. Canned milk samples can be stored at a temperature of 4-b "up to 10 days. Samples are stored in clean vials, closed with stoppers.

The quality of milk is determined in a complex of organoleptic, physico-chemical, and if milk is suspected to be contaminated with pathogenic microflora and bacteriological studies. Freshly milked milk is characterized by the following organoleptic and physical properties.

Organoleptic study of milk

Appearance - homogeneous liquid of white color with slightly yellowish shade. The color of milk is determined in a glass cylinder by viewing it in reflected light. Colostrum is yellow or yellow-brown. A change in the color of milk is noted in some diseases of cows. For example, with leptospirosis and some forms of mastitis, milk has a yellow color. The yellow color of milk is observed when cows are fed a large amount of carrots and corn. Milk becomes reddish when cows are sick with piroplasmosis, pasteurellosis. anthrax and hemorrhagic mastitis, as well as in case of violation of the rules of machine milking, when, after the end of milk transfer, milking cups are overexposed on the nipples. Feeding cows large amounts of certain plants in the buttercup, euphorbia, and horsetail families will also give the milk a reddish color. Red or pink milk occurs with the development of pigment bacteria in it, a wonderful stick, etc. Therefore, in each case of a change in the color of milk, it is necessary to establish its causes.

The smell of milk is specific When determining the smell - cold milk is heated in a flask or test tube to a temperature of 25-30 °. In cold milk, the smell is recognized worse. In benign milk, the smell is pleasant, specific. Milk acquires odors when stored with odorous substances (kerosene, fish, sauerkraut, creolin, etc.). Milk acquires a dung (shed) smell when it is filtered not to milk, but in a dirty barn, as well as when particles of manure get into the milk. A musty smell appears when freshly milked milk is stored in a tightly closed container. In such cases, putrefactive microorganisms multiply abundantly, hydrolyzing milk proteins. Milk has a silage smell when cows are fed low-quality silage, as well as when silage is stored in a barnyard.

The taste of milk is pleasant, slightly sweet. To determine the taste, the milk is slightly heated. Then take a sip of milk in your mouth and rinse your mouth with it to the root of the tongue. Certain feeds can have a negative effect on the taste of milk. For example, radish, turnip, rutabaga, colza, field mustard, fed in large quantities, gives a rare taste to milk. It has a salty taste of milk at the end of lactation, when mixed with colostrum, with udder tuberculosis and mastitis.

A bitter taste is caused by cows eating a large number of bitter plants: wormwood, lupine, buttercups, burdock, beet tops, turnip, it has molded spring straw, rancid oilcake. During long-term storage of milk or dairy products at low temperatures, cold-resistant microorganisms develop in them, giving milk, cream, sour cream and butter a rancid taste. In this case, the decomposition of milk fat occurs with the formation of butyric acid, aldehydes, ketones and other substances that cause this taste. Milk acquires a soapy (alkaline) taste when it is contaminated with putrefactive bacteria.

The consistency of milk is homogeneous. It is determined by slowly pouring milk from one container (cylinder, beaker, etc.) into another. The admixture of flakes or clots in milk indicates a disease of the mammary gland. Mucous (viscous) milk is caused by some races of lactic acid streptococci, lactobacilli, etc.

Density. The density of milk is the ratio of its mass at a temperature of 20 ° to the mass of water of the same volume at 4 °. The density of milk characterizes to a certain extent its naturalness. Density wholeness of milk ranges from 1.027 to 1.033, average - 1.030. Density skimmed milk is within 1.038, on average - 1.035. When skimmed milk is added to whole milk, the density of the latter increases, and when water is poured, it decreases. Every 10% of water added to milk reduces its density by three divisions of the hydrometer scale, or by 3°. With the addition of skim milk or the removal of fat, the density of milk increases accordingly. However, if you remove cream from milk and then add the same amount of water, its density will not change. Such falsification is called double - For identification, it is necessary to determine not only the density of milk, but also the content of fat in it.

Milk density is determined not earlier than 2 hours after milking and at a temperature not lower than 10° and not higher than 25°. The density of milk is determined by a special milk hydrometer (lactodensimeter) at a temperature of 20 °.

Method for determining the density: 200 ml of the test milk is poured into a glass cylinder and a milk-pyG1 hydrometer (lactodensimeter) is lowered. The reading is made on the scale of a thermometer and a hydrometer. If the milk temperature is 20 °, then the readings of the hydrometer scale correspond to the actual density. Otherwise, correct for temperature. Each degree of deviation from the normal temperature (20°) corresponds to a correction equal to +-0.2 degrees hydrometer. At a milk temperature above 20 °, the density will be lower and the correction is made with a plus sign. At a milk temperature below 20 ° - with a minus sign.

Research methodology: pour 1 ml of the milk under test into a test tube, add 2 drops of a 10% solution of potassium chromate and 1 ml of a 0.5% solution of silver nitrate. Shake the vial with the contents. Conditioned milk turns lemon yellow, and milk diluted with water turns brick red.

Determination of ketone bodies in milk. To 5 ml of the investigated milk in a test tube add 2.5 g of ammonium sulfate. 2 drops of 5% aqueous solution sodium nitropruside and one ml of 25°/o aqueous ammonia solution. Shake the tube and read the reaction after 5 minutes. In the presence of ketone bodies, the mixture becomes pink. Such milk is discarded.

Determining the percentage of fat in milk

Determination of fat in milk is carried out by the sulfuric acid method. It is based on the dissolution of milk proteins with sulfuric acid, as a result of which fat is released into pure form. As a solvent, sulfuric acid with a density of 1.81-1.82 and isoamyl alcohol with a density of 0.811-0.812 are used.

Research methodology: 10 ml of sulfuric acid is poured into the milk butyrometer using an automatic pipette, then 10.77 ml of milk and 1 ml of isoamyl alcohol are poured carefully (along the wall). The butyrometer is closed with a rubber stopper, wrapped in a towel and gently stirred until the contents are completely dissolved. Then the butyrometers are placed with the stopper down and a water bath at a temperature of 65-70 ° for 5 minutes. The butyrometer removed from the bath is subjected to centrifugation for 5 minutes. After centrifugation, the sheaf is placed in a water bath for 5 minutes, after which the amount of fat is counted on the butyrometer scale. Each large division corresponds to 1% body fat, and each small division corresponds to 0.1%. In accordance with the standard (GOST 13264-67), whole milk must contain at least 3.2% fat.

Determination in skimmed milk. It is produced in the same way as in whole milk, by the sulfuric acid method, but in special butyrometers with a scale divided into tenths and hundredths of a percent. In such butyrometers pour in double the amount of all included in the analysis whole milk ingredients: 20 ml of sulfuric acid, 21.54 ml of skimmed milk and 2 ml of isoamyl alcohol. The exposure in a water bath before and after centrifugation is the same, but three times centrifugation is used.

Determination of the acidity of milk

Freshly milked milk has an amphoteric reaction. The increase in the acidity of milk is due to the breakdown of milk sugar to lactic acid, due to the development of lactic acid and other bacteria. The longer milk is stored unrefrigerated, the more lactic acid accumulates in it.

Freshly milked milk from a healthy cow has 16-18° acidity. Increased acidity can be observed in the milk of cows grazing in summer time in places with sour cereals or in wet meadows. The acidity of colostrum reaches 50° Turner, and at the end of lactation it drops to 12-14°. With mastitis, the acidity of milk decreases to 7-15 ° Turner. Cow's milk, procured for state and cooperative purchases on collective farms, state farms, and other farms, must not have an acidity above 20°. The acidity of milk of the first grade is usually 16-18 °, the second grade - 19-20 ° and off-grade - 21 °.

Determination of the titratable acidity of milk. Titratable acidity is indicated in degrees of titration - T°-Turner. The degree of acidity is the amount of ml of a decinormal alkali solution used to neutralize 100 ml of milk.

Research methodology: 10 ml of the investigated milk, 20 ml of distilled water and 3 drops of 1% phenolphthalein are poured into a conical flask and titrated with 0.1 alkali solution until a slightly pink color appears, which does not disappear within one minute. The number of milliliters of alkali used for titration, multiplied by 10, shows the degree of acidity of the milk under study. With mass acceptances of milk in the markets, the determination of the maximum acidity is carried out.

Extreme acidity. The maximum acidity is the degree of acidity of milk, above which milk is not allowed to be sold. When selling milk on the markets, the maximum acidity should not be higher than 20 "and lower than 16 °.

Research methodology; 10 ml of 0.01 N alkali solution is poured into a row of test tubes placed in a rack, which is prepared as follows: 100 ml of 0.1 N alkali solution and 10 ml of 1% phenolphthalein solution are measured into a liter flask, distilled water is added up to 1 litre. Pour 5 ml of milk into a test tube with 10 ml of the indicator. If the acidity of milk is below 20 °, then an excess of alkali remains in the test tube and a pink color remains; if the acidity is above the limit, then there is not enough alkali to centralize it and the liquid in the test tube becomes discolored. An increase in the acidity of milk can occur when cows are fed spoiled silage or pulp containing oxalic acid, as well as when cows are fed excessive amounts of concentrated feed. An increase in acidity, as well as in the density of milk, is noted in the initial stage of mastitis in cows.

Determination of purity of milk

One of the main indicators characterizing the quality of milk is the degree of its purity. Filtering dirty milk. no matter how carefully it is carried out, it does not improve its quality, but on the contrary, it deteriorates faster, because the dirt inactivates the bactericidal and bacteriostatic substances contained in it (lysozyme, lactenins, bacterilysins, etc.).

Determination of the degree of purity of milk. The purity of milk is determined using the device "Record". 250 ml of milk is passed through the device, the filter is dried and compared with special standards, on the basis of which I establish the milk purity group.

According to the degree of contamination, milk is divided into 3 groups. The first group includes milk, during the filtration of which the precipitate is almost not noticeable. The second group includes milk that has traces of contamination on the filter (in the form of small dots). In the milk of the third group, contamination is clearly expressed. Mechanical suspension is visible on the filter in the form of larger dots, the color of the filter is gray.

According to GOST 13264-67, milk of the first grade must have a purity of group I, milk of the second grade - group II and non-grade - not lower than group III.

Determining the presence of soda in milk. Sometimes, in order to protect milk from curdling in case of high acidity, soda is added to it. However, soda does not increase its resistance, but on the contrary, favorable conditions are created for the development of putrefactive microflora. To determine soda in milk, indicators are used: rosolic acid, bromthymol blue. phenolrot.

Research methodology: 1 ml of the investigated milk sticks into a test tube and the same amount of a 0.2% solution of roseolic acid is added. Milk that does not have an admixture of soda with roseolic acid acquires an orange color, and those containing soda become raspberry red.

Checking the quality of milk pasteurization

On farms disadvantaged by infectious diseases of cattle, milk is pasteurized. In this regard, there is a need to control the quality of pasteurization. To check the quality of pasteurization on farms, a peroxidase test is used, and in the dairy industry, a phosphatase test.

Reaction to peroxidase: if a few drops of potassium iodine starch solution and one drop of hydrogen peroxide solution are added to raw milk, the following reaction will occur: peroxidase + H2O2 + 2KOH + starch == 2KOH + J2 + starch, i.e. a blue color appears. In milk heated to 80-85 °, a color change will not occur, since peroxidase is destroyed when heated.

Research methodology: Add 5 drops of potassium iodide starch (3 g of potassium iodide and 3 g of starch per 100 ml of water) and 5 drops of 1% hydrogen peroxide solution to 3-5 ml of the test milk in a test tube. The appearance of an intense blue color indicates the presence of peroxidase in the milk. Therefore, such milk has not been pasteurized. The appearance of a pale blue color indicates the partial destruction of the enzyme under the influence of a temperature of 65 - 70 ° on the milk, that is, the milk is not pasteurized enough.

Phosphatase reaction. The phosphatase enzyme is less heat resistant than peroxidase. Therefore, this reaction can establish the correct observance of the regime of low pasteurization, which is used in dairies.

Research methodology; 2 ml of the test milk and 1 ml of sodium phonolphthalein phosphate solution are poured into a test tube, closed with a cork and after thorough mixing, the test tube is placed in a water bath at 1 40-45 °. The reaction is read after 10 minutes. In a test tube with properly pasteurized milk, no changes are observed. If the pasteurization mode is violated, when the phosphatase remains in the active state, the contents of the tube take on a bright pink color.

Determining the class of milk

Classification of milk is a chemical method for determining the degree of contamination of milk with microflora. It is established by a reductase test.

Determining the classiness of milk, we tentatively establish that the microflora, multiplying in milk, releases its metabolic products - reductase, which has the property of discoloring some paints, in particular methylene blue or changing the color of resazurin. Consequently, the more microflora is contained in milk, the more reductase is released and the faster methylene blue discolors or the color of resazurin changes.

Reductase test with methylene blue is carried out as follows; 1 ml of methylene blue solution (5 ml of a saturated solution and 195 ml of distilled water) is poured into a test tube and 20 ml of the test milk is added. If there are no large test tubes, ordinary ones can be used, but the amount of milk and reagent is halved. After stirring, put in a water bath at t 38-40 ° and every 15-20 minutes observe the discoloration of the contents of the tube.

According to the time of onset of discoloration, the good quality of milk is determined, as can be seen from the data in the table: good quality of milk and class.

The disadvantage of the reductase test with methylene blue is that it poorly captures the contamination of milk in winter. If during milking (in unsanitary conditions) bacteria get into the milk and it is immediately cooled to 4 ° and below, then the biochemical activity of microorganisms is delayed. In addition, milk with streptococcal mastitis according to the reductase test with megilenope blue can be of the first class.

Reductase test with resazurin. Due to the fact that the test with methylene blue has disadvantages, a resazurin test is used.

Method: 10 ml of the test milk is poured into a test tube and 1 ml of a 0.05% solution of resazurin is added. The test tubes are closed with sterile stoppers, placed in a water bath at 42 - 43 ° and the time is noted. Observation is carried out after 10 minutes and 1 hour. Resazurin under the influence of reductase is restored to refurin (pink).

This test makes it possible, relatively faster than with methylene blue, to obtain the results of assessing milk according to the degree of bacterial contamination. It is very important that this sample is the milk of cows with mastitis.

To increase the effectiveness of the resazurium test, I.S. Zagaevsky suggested adding 0.5% formaldehyde to a 0.05% solution of resazurin, as a result, the light sensitivity of the indicator in milk decreases and the accuracy of the analyzes increases.

The results of this test are taken into account according to the following indicators

first class - blue-blue color in vitro,

second class - blue-violet,

third grade - pink.

It should be noted that the reductase test with resazurin. compared to methylene blue, speeds up the analysis by more than five times. Continuous monitoring of the reaction is not required. It reveals the reductase of all microorganisms that seed milk is more demonstrative when reading the reaction to the classiness of milk.

Microbiological analysis of milk

Microbiological examination of milk is carried out in the following cases:

1) when it is suspected that it may pose a danger to human health,

2) in order to control the sanitary and hygienic regime of milking and primary processing of storage and transportation,

3) in case of suspected contamination with microorganisms, in the presence of which milk cannot be processed into dairy products,

4) to establish the microflora that caused inflammation of the mammary gland and its antibiotic resistance.

In most cases, the microbiological examination of milk is limited to determining the total number of bacteria and the fermentation titer. If contamination of milk with pathogenic microorganisms is suspected, special studies are carried out depending on the type of alleged pathogen. Milk must be examined immediately after sampling, otherwise it should be cooled to 4-6 ° (not higher). Labels are attached to the dishes with milk samples for research indicating the sample number, the number and size of the batch of the product, the day and hour of sampling. The label must be signed by the person who took the sample, indicating his position. If milk samples are sent to a laboratory located outside the enterprise (collective farm, state farm), they are sealed and sealed.

cup method. To determine the total number of microbes in milk, the test material is introduced into a Petri dish and filled with a nutrient medium in an amount of 12-15 ml. During the study, it is necessary to make a preliminary dilution of milk in sterile water. Dilutions are made in such a way that the last of them contains a dozen cells in 1 ml. For inoculation on Petri dishes, the last three dilutions are usually used. Seeded cups are placed in a thermostat at a temperature of 37 °. Count grown colonies produced after 24 and 48 hours. The number of colonies in each dish is multiplied by the degree of dilution of the milk. From each milk sample, colonies should be counted on three plates and averaged. The sum of colonies in all cups is divided by the number of cups and thus the index of microbial contamination of 1 ml of milk is established.

Express methods for detecting E. coli and Salmonella bacteria in milk and equipment

To determine the quality of milk and dairy products, it is important to establish not only the total number of microbes contained in them, of which some have useful qualities. but also to identify the bacteria of Escherichia coli (Escherichia), which are sanitary-indicative microorganisms. Detection of these bacteria in milk, dairy products and objects that come into contact with milk indicates unsatisfactory conditions for milking crowns, violations of the rules for processing milk on farms, contamination of it with manure, bedding, poor preparation for milking udders, milking equipment, non-compliance with the rules of personal hygiene of milkers or dairy workers,

However, the complexity and multi-stage nature of studies of milk and equipment for contamination with coli bacteria makes it difficult to systematically control the sanitary quality of milk and products made from it. Therefore, we proposed PZh-65 medium for this purpose, which allows us to give an answer in a short time about the degree of contamination of milk, dairy products and milking equipment with coli bacteria.

Medium PJ-65 is intended for isolation of E. coli and Salmonella bacteria from milk, cream, sour cream, cottage cheese, butter and cheeses. The medium is prepared according to the following recipe (in g): lactose 20.0. potassium phosphate (disubstituted) - 3.0, nutrient agar (in powder) - 50.0, sterilized cattle bile - 100 ml, 1% alcohol solution of brilliant green - 2 ml. The indicated components are dissolved with heating and stirring in 900 ml of distilled water, the pH is set to 7.2-7.3, poured in a column into test tubes of 5 ml, heated with flowing steam at 100 ° for 15 minutes, cooled to 45-46 ° and make in test tubes with milk dilution medium or dairy product, previously pounded in a sterile mortar with a physiological solution of sodium chloride aCl, Seedings from milk and products are made in dilutions of 1: 5, 1: 10, 1: 100, 1: 1000, etc. Incubated in a thermostat at a temperature of 43-44C.

In the presence of Escherichia in the product, even in dilutions up to 10 "9, after 16-18 hours of incubation, a column of the medium breaks, but its initial green color does not change. With the growth of Salmonella, the medium acquires olive color, without breaking its mass. Gram-positive microorganisms do not develop on PZh-65 medium. A production check of this medium in ten regional veterinary laboratories of Ukraine showed that it significantly reduces the analysis time when E. coli bacteria are found in milk and dairy products.

Indication in milk of staphylococci

There is a connection between the occurrence of staphylococcal diseases and the consumption of milk of animals with mastitis. In primary crops on meat-pentone agar, staphylococcal cultures form a golden, orange, brown, white or gray pigment. When reseeding staphylococci, the shades of the pigment and the intensity of its formation change. Hemolysis rates (alpha or beta) in individual cultures are also not constant, they fluctuate depending on the freshness of the blood, the concentration of erythrocytes in the agar, the thickness of the medium layer on Petri dishes, temperature, duration of incubation and other conditions. Often the same culture of pathogenic staphylococcus, depending on the growing conditions, will give different types of hemolysis. When the epithelium of the nipple canals in cows is injured by faulty milking machines, which causes inflammation of the mammary gland, or if the milk tank is damaged, staphylococci are sown from milk in almost 100% of cases.

For the isolation of staphylococci from milk, I.S. Zagaevsky suggested Wednesday P-3. For its preparation, 30.0 g of sodium chloride, 30.0 of nutrient agar (in powder), 10.0 g of glucose, 0.8 g of sodium carbonate, 0.25 I of sodium sorbinate are dissolved in 500 ml of liver broth. The mixture is heated at 100 "C for 30 minutes. The pH is adjusted to 7.3-7.4 and before pouring into Petri dishes (at an ambient temperature of 47-48 ° C), 40 ml of fresh defibrinated blood of cattle is added. the advantage of rabbit drop in the hemolysis reaction by pathogenic staphylococci in comparison with the blood of cattle, the content of sodium chloride in the medium over 6.5% slows down the hemolysis of erythrocytes by staphylococci.Agar is formed around the colonies of pathogenic staphylococci (a zone of hemolysis of erythrocytes).

One of the most important criteria for differentiating pathogenic staphylococci from saprophytic ones is the plasma coagulation reaction. It has been established that when adding 2 drops of pathogenic staphylococcus broth culture or 5 drops of milk from udder lobes affected by staphylococcal mastitis to 2 ml of pig blood plasma, plasma coagulation occurs at a temperature of 38-40 ° for 1 1/2 hours, at a temperature of 25-30 ° for 3-12 hours, at a temperature of 20-22°C for 6-18 hours. The reaction of plasma coagulation with whole plasma is more demonstrative than with diluted one. The optimal temperature for plasma clotting is 38 ° C. Rabbit and pig blood clotting occurs almost at the same time. Pathogenic staphylococci do not coagulate the blood plasma of sick animals treated with antibiotics, as well as non-fresh plasma.

Sanitary assessment of milk in case of animal diseases

Tuberculosis. The greatest danger is the milk of animals with lesions of the udder tuberculosis, which always contains a large number of tubercle bacilli. In the pulmonary form of animal tuberculosis, the pathogen is initially found in saliva, which can enter manure through the digestive tract, and then from animal skin or bedding into milk.

Tuberculous mycobacteria are very heat resistant compared to other pathogenic non-spore bacteria. According to our research, tuberculosis bacilli in cattle are inactivated only when they are heated to 85 "" for 30 minutes, in cottage cheese and butter they survive up to 3 months, and in hard cheeses- about 8 months (observation period).

The increased resistance of tuberculous mycobacteria is associated with the presence of a waxy dense shell in them. Therefore, the temperature and time in the accepted modes of pasteurization of milk do not always ensure the death of these bacteria.

In accordance with the current rules, milk obtained from animals with tuberculous lesions of the udder is subject to destruction under the supervision of veterinary supervision. Milk obtained from animals that respond positively to tuberculin and do not have clinical signs of the disease must be boiled and used on the farm. Such milk can be processed into melted butter, and the skimmed milk obtained during the processing of this butter, after boiling, is used as animal feed. Milk, from non-reacting to tuberculin animals, healed economy, subjected to pasteurization at t 85° for 30 minutes or 90° - 5 minutes.

Brucellosis. Brucella in milk multiply slowly, and at temperatures below 20 °, their development stops. Their survival in dairy products is quite high. So, in fermented milk products they remain viable for up to 2 weeks, in cheese - 1.5 months.

The presence of brucella in milk is determined using a ring test, which is based on the presence of corresponding antibodies in the milk of animals with brucellosis. A suspension of killed Brucella stained with hematoxylin or other dye is used as an antigen. As a result of adding color antigen 13 to the milk of a cow with brucellosis, the antibodies located there adhere to the antigen. The resulting antibody + antigen complex has the ability to be adsorbed on the surface of fat globules, which rise up at 37-38°, dragging the glued bacteria with them. Therefore, with a positive reaction, a blue ring of stained Brucella cells is formed in the upper layer of the cream. If the test results are negative, the top layer of the cream is not stained, and the milk takes on the color of the paint with which the antigen was stained. According to the instructions for combating brucellosis, milk from cows. having clinical signs of brucellosis and reacting to brucellisate are boiled on the farm for 5 minutes and used inside the farm. Milk from cows that do not respond to brucellosis, health-improving farms, is subjected to pasteurization at a temperature of 80 ° for 30 minutes. In sheep farms that are unfavorable for brucellosis, sheep are not milked.

FMD. When cows are infected with foot and mouth disease, there is a decrease in milk yield, an increase in milk leukocytes, fat, as well as albumin, globulin and calcium. Along with this, the amount of vitamin A and riboflavin in the milk of sick cows decreases. The stability of the foot-and-mouth disease virus is as follows: in fresh milk at 37 ° it lasts 12 hours, at 5 ° - 12 days, in milk cooled to 4 ° - 15 days. When milk is soured, the virus in it is inactivated when exposed to increased acidity.

According to the instructions for the fight against foot-and-mouth disease, when quarantine is imposed on a household that is unfavorable for foot-and-mouth disease, it is prohibited to export and use milk and dairy products in a non-dehydrated form. Milk obtained from animals quarantined for foot-and-mouth disease can be allowed to be consumed after pasteurization at 85 "for 30 minutes or boiling for 5 minutes. If foot-and-mouth disease is complicated by purulent mastitis, the milk is boiled and destroyed.

Prevention of mastitis in cows in dairy complexes and farms

One of the factors that worsen the quality of milk and reduce the productivity of dairy cattle breeding is the disease of cows with mastitis.

According to the World Veterinary Health Organization, mastitis causes more damage than all cow diseases combined. The damage consists of: premature culling of cows, shortage of milk and calves, deterioration of the biological, technological and nutritional qualities of milk, an increase in the disease of calves due to drinking colostrum or milk from animals with mastitis, increased infertility of cows, costs for diagnosis, treatment, etc. In addition to economic, mastitis also causes social prejudice. since mastitogenic microbes cause disease in humans, especially children.

Mastitis occurs as a result of a combination of microbial and predisposing factors, the most important of which are: violation of the rules for feeding, keeping and milking cows, malfunction of milking equipment, unsatisfactory implementation of preventive measures on farms, as well as untimely detection and treatment of mastitis occurring in a latent form.

Depending on the resistance of the cow's organism, the virulence and lathogenicity of the mastitogenic microflora, as well as the duration of the action of predisposing factors, mastitis occurs in a clinical or latent form, the so-called subclinical mastitis. The latter represents focal inflammation of the breast parenchyma and is found 10-12 times more often than the clinical forms of this disease.

With untimely detection and treatment of mastitis, as well as under the influence of adverse environmental factors, subclinical mastitis turns into clinically pronounced inflammation, which often ends in atrophy of the affected udder lobes. With clinical mastitis, the entire lobe of the udder or several lobes is inflamed, and with subclinical mastitis, there is a small inflammatory focus in the parenchyma of the udder, most often with a size of Walnut. Therefore, clinical symptoms are invisible and there are no organoleptic changes in milk. However, the qualitative composition of milk changes in the affected parts of the udder. It reduces the content of casein, calcium, lactose, essential amino acids, vitamins and other substances. It is impossible to prepare high-quality dairy products from such milk. Even a small admixture of mastitic milk in the combined (6-10%) significantly worsens the quality of the cheese and reduces the yield of this product.

Currently, there are no restrictions on milk for subclinical mastitis of cows, it enters the total milk yield and is used as food for people. And this despite the fact that it is often seeded with pathogenic and toxigenic microflora. When cows become ill with mastitis, even in a subclinical form, the composition of colostrum deteriorates. When fed to calves, it retards their growth and development and often causes diseases of the gastrointestinal tract and respiratory tract. An increased incidence of mastitis in cows is observed in farms that do not carry out the prevention of this disease.

The immediate causes of mastitis in cows are: violations of the rules for machine milking of cows, lack of selection of cows suitable for machine milking, insufficient qualification of milkers, feeding cows during calving or launching an excess amount of concentrates and succulent milk-processing feeds, hypothermia of the udder on a damp, cold and dirty floor cowsheds or on unimproved walking grounds, lack of insulators on farms, keeping heifers and first-calf heifers together with old cows carrying mastitis pathogens, insufficient maintenance of milking equipment, under-milking or milking, the so-called idle milking, washing the udders of several cows with non-replaceable water, dressing on teats cold teat cups, violations of the daily routine on farms, etc.

Due to the wide spread of mastitis, from 27 to 35% of cows are culled annually on farms, in most cases for 2-3 lactations. If we take into account that the productivity of cows can last 10-12 lactations, then at least 6-7 calves are lost from each prematurely culled cow and milk is not received from 6-7 lactations.

The success of the fight against mastitis in cows and the prevention of this disease depends on the timely diagnosis of a latent (subclinical) form of inflammation of the mammary gland. Early detection and timely treatment of subclinical mastitis prevents exacerbation of the disease into a clinical form and udder atrophy. Therefore, much attention is paid to the diagnosis of subclinical mastitis in cows.

As a stall test for the diagnosis of latent forms of mastitis, an analogue of a mastitis diagnostician, mastitis tests, has proven itself well on farms. To prepare it, 200 g of sodium tripolyphosphate, 100 g of sulfanol and 5 g of sodium hydroxide are dissolved in one liter of hot tap water. After the above ingredients are dissolved, the indicator is ready for use. When mixing 1 ml of the mastitis test with 1-2 ml of the test milk, in positive cases, flakes and a clot are formed during a few seconds while stirring the mixture. The mixture of mastitoprobe with milk from healthy cows is homogeneous. Mastitoprob does not give a positive reaction with colostrum, injuries of the mammary gland, does not react with the milk of healthy cows, but is specific only for the detection of milk obtained from udder lobes affected by mastitis. Timely detection of subclinical mastitis by mastitoprobe and its rational treatment prevents udder atrophy.

Due to the fact that on farms it is laborious to diagnose a latent form of mastitis from each quarter of the udder, therefore milk from the milking bucket is examined with a mastitis test, that is, silt from all the fourth udder at the same time. In the case of a positive reaction, the affected lobes are specified.

Mastitoprob can be used to test the effectiveness of the treatment of cows with mastitis. A cow is considered cured if the reaction to mastitis is negative during a three-fold check of mastitis tests (every other day). Mastitoprobes are used in laboratories of collective farm markets, milk collection points and enterprises of the dairy industry to detect impurities in the milk of cows with mastitis.

Before sampling at the factories, the milk is thoroughly mixed. The study is carried out in test tubes or milk-control plates, however, it is more convenient to read the reaction in test tubes.

For research with the help of a beak machine, 1 ml of the mastitis test is poured into test tubes, 1 ml of the milk under study is added, slightly mixed and labeled according to the containers from which the milk sample was taken. When the mastitoprobe interacts with the milk of cows with mastitis, the reaction occurs within 1-2 minutes. To read the reaction, it is advisable to use the standard of various dilutions of obviously mastitis milk (clinical form) in the milk of healthy cows. The reaction is taken into account with semi-horizontal rotation of the test tube. In the absence of admixture of milk from cows with mastitis, the mixture is homogeneous, without mucus and flakes. The degree of reaction is estimated in crosses, which correspond to a certain percentage of admixture of mastitis milk in the combined, namely: four crosses (++++) - the formation of a jelly-like clot in the mixture of the drug with milk. Such milk contains over 25% mastitis impurities. A moderate clot in the form of a dense protein of a chicken egg indicates an admixture of 20-25% mastitis milk, - three crosses (+++) - the transformation of a mixture of milk with the drug into a mucous viscous mass. Such milk contains 15-20% mastitis, - two crosses (+ +) - the presence of an abundant amount of flakes and mucus of a liquid consistency. Milk contains 10-15% mastitis impurities. A small amount of mucus in a test tube indicates an admixture of 5-10% mastitis milk in the combined, - one cross (+) - detection of single mucous strands or flakes in the mixture. Such milk contains 1-5% mastitis.

With the help of a mastitis test, it is possible to reveal the degree of spread of mastitis on farms supplying milk to dairy enterprises within 1.5-2 hours and signal farms to take measures to combat this disease.

In the fight against mastitis in cows, we have introduced a set of anti-mastitis measures in three dairy complexes and two farms. The main ones are to eliminate the factors that contribute to the disease of cows with mastitis.

Experiences in the introduction of anti-mastitis measures have shown that mastitis in cows can be successfully combated, but for this it is necessary, first of all, to identify and eliminate factors on farms that contribute to the emergence and spread of this disease. In addition, it is necessary to timely identify the initial stages of inflammation of the mammary gland and subject them to immediate treatment.

It should be noted that the fight against mastitis has not only economic but also social significance, since mastitis pathogens (streptococci, staphylococci, Escherichia, etc.) cause disease in people. Due to the fact that the causes of mastitis are diverse, the fight against it should consist of a complex of veterinary and sanitary, zoohygienic, zootechnical and economic and organizational measures. If any link is omitted from this complex, then the effectiveness of the fight against mastitis is sharply reduced. Practice shows that with careful implementation of the specified complex, the fight against mastitis can be successful, but for this it is necessary to eliminate the factors that contribute to its occurrence on farms. It is also necessary to timely identify the initial stages and forms of inflammation of the mammary gland, which should mean not only subclinical mastitis, but also the initial stages of serous and catarrhal mastitis. After detection, it is necessary, without delay, to subject the sick cows to rational treatment. Untimely detection, delayed or irrational treatment of mastitis causes atrophy of the affected udder lobes. As a result, the cow becomes dairy-free, and therefore economically unsuitable.

It should be noted that the fight against mastitis in cows is a complex, lengthy, laborious process and its implementation requires considerable costs. For example, mastitis cannot be eliminated when cows are kept on cement floors in winter. The successful fight against mastitis is also unpromising when using worn-out milking equipment on the farm or insufficient qualification of milking operators. However, comparing the damage caused by mastitis and the costs of taking measures to eliminate it, it turns out that the amount of damage is several times higher than the costs necessary to successfully combat mastitis in cows.

In connection with the fact that mastitis pathogens cause diseases in people, especially children, it is advisable to have several farms in each area that are free from this disease in order to supply hospitals and children's institutions with good-quality milk. These farms must be under close veterinary supervision.

In each farm, groups of healthy cows should be allocated for feeding the calves with good-quality colostrum and milk.

Bibliography

1. Abramova-Obolenskaya N.I., Vasiliev L.G., Presnova S.F. Ways of infection of dairy products and measures for their suppression // Proceedings of MNIIEM im. G.N. Gabrichevsky - T. XXI, 1979.

2. Bannikova L.A., Koroleva N.S., Semenikhina V.F. Microbiological bases of dairy production. - M.: Agropromizdat, 1987.

3. Gorbatova K.K. Biochemistry of milk and dairy products. - Light and food industry, 1984.

4. Goreglyad Kh.S., Kozhemyakin N.G., Koryazhnov V.P., Shlipakov Ya.P. Veterinary and sanitary expertise with the basics of animal products processing technology. - L: Kolos, 1985.

5. Zagaevsky I.S. Veterinary and sanitary expertise with the basics of animal products processing technologies. -5th ed., revised and expanded. - M.: Agropromizdat, 1989. -207 p.

6. Makarov V.A. and other Veterinary and sanitary expertise with the basics of technology and standardization of animal products. - M.: Agropromizdat, 1991. - 463 p.

7. Guide to veterinary sanitation / Polyakov A.A., Bocharov D.A., Volkova I.I. and etc.; ed. Polyakova A.A. – M.: Agropromizdat, 1986.

9. Guidelines for veterinary and sanitary examination and hygiene of animal products processing. / ed. Shur I.V. –M.: Kolos, 1959.

10. Hygienic requirements for the safety and nutritional value of food products. Sanitary and epidemiological rules and regulations. SanPiN 2.3.2.1078-01.

Milk and dairy products are valuable products nutrition of animal origin. However, it should be remembered that milk obtained from sick animals can be a source of human infection with zooanthroponotic diseases, in addition, if sanitary rules and the technology for obtaining and processing and storing milk and dairy products are violated, they can cause food toxicosis and toxic infections. Therefore, one of the most important tasks of the veterinary service is the proper organization of the veterinary sanitary examination of milk in order to control their quality and safety at all stages (receipt, transportation, processing, storage and sale). The procedure for the veterinary sanitary examination of milk and dairy products is determined by the current regulatory documents.

Purchasing requirements for milk

Requirements for natural cow's milk are set out in GOST R 52054-2003, which came into force on 01.01.2004. This normative document regulates the quality and safety of milk, and methods of their control, as well as the rules for the acceptance and labeling of this product.

All milk must be obtained from healthy animals on farms that are free from infectious diseases, in accordance with the current veterinary and sanitary regulations and the international veterinary code. All purchased milk, depending on its organoleptic and laboratory parameters, is divided into three grades, see table. 4. The basic all-Russian norms for the content of fat and protein in milk are 3.4% and 3%, respectively.

Table 1

Milk indicators according to GOST R 52054-2003

Name of indicator	Top grade	First grade	Second grade	Unsorted
Consistency	Homogeneous liquid without sediment and flakes Freezing not allowed			The presence of flakes and fur. impurities
Taste and smell	Specific, without foreign odors and flavors characteristic of natural milk.		Allow mild forage in the spring-winter period	Pronounced fodder taste and smell
	White to light cream			Cream or gray
Acidity°T			16 to 20.99	Less than 15.99 or more than 21
The group is purely you are not below
Density kg/m3				Less than 1026.9
Temperature Freezing °С	Not higher - 0.52

It is forbidden to use for food purposes milk obtained from cows in the last 5 days before launch and the first 7 days after calving. If unsatisfactory results of the analysis are obtained for at least one indicator, a second analysis is carried out using a double sample volume from the same batch of milk. The results of the reanalysis are final.

Milk after milking must be filtered and cooled to a temperature of 4±2°C for 2 hours. Milk should be kept at 4°C for no more than 24 hours at the dispenser.

When sending milk, a veterinary certificate form No. 2 (certificate form No. 4 for the region), a certificate of quality and safety and a consignment note (for legal entities) are issued. Milk is transported by specialized vehicles (in tanks for food liquids, metal flasks or other containers permitted by the RF Sanitary and Epidemiological Supervision) in accordance with the rules for transporting perishable goods at a temperature of +2 to +8 ° C for no longer than 12 hours. If the transportation regimes are violated, milk is referred to as off-grade.

Veterinary and sanitary examination of milk

To determine the quality and safety of milk, it is necessary to study the accompanying documents, assess the sanitary condition of containers and transport, and conduct a set of organoleptic, physico-chemical and microbiological studies.

Study of accompanying documents

When milk is delivered to the market by private individuals, they must submit a veterinary certificate form No. 2 or a veterinary certificate form No. 4 (when transported within the district). When studying this document, special attention should be paid to the epizootic state of the settlement from which the milk came, to the timing and results of routine diagnostic tests (for tuberculosis, brucellosis, etc.), vaccinations and tests for latent mastitis. This document is valid for 1 month. In addition, a person selling milk in the market must have a sanitary book of the established form.

If the supplier is an organization, then for each batch of milk a veterinary certificate form No. 2 or a veterinary certificate form No. 4 (when transported within the region) is issued for a period of validity of 3 days, a bill of lading, and a quality certificate indicating the results of milk testing received in the dairy laboratory of the farm. When supplying dairy and milk-containing products and pasteurized milk, a certificate of conformity and a hygiene certificate or their certified copies are additionally required.

Inspection of transport containers

Milk and dairy products are easily contaminated and adsorb strong-smelling substances. Therefore, milk containers must be hermetically sealed. In addition, milk tata must be made from food-grade material approved by the RF Sanitary and Epidemiological Supervision and be sanitary-clean.

Most often for milk transportation I use special milk tankers, milk flasks made of aluminum and stainless steel, enamelware without chips, containers made of glass and food-grade plastic. In transport, milk cannot be transported together with strongly smelling, toxic and dusty substances.

Taking milk samples and preparing them for analysis

Milk sampling is carried out at the place of its acceptance in accordance with GOST 13928-84 and GOST 26809-86.

An average sample of 500 ml is taken from a batch of milk for the study. Before sampling, the milk is thoroughly mixed, moving it up and down in flasks with a whorl 8-10 times, in road and rail tanks with mechanical mixers 3-4 minutes and 15-20 minutes, respectively. When taking spot samples of milk, mugs with elongated handles with a capacity of 0.25 or 0.5 or samplers (cylindrical tubes with an inner diameter of 9 mm made of stainless steel, aluminum or food grade plastic) are used. When sampling with a sampler, it must be lowered into the container slowly, with the upper end open. The selected samples are placed in a clean container made of a material approved by the Sanitary and Epidemiological Supervision of the Russian Federation, with a hermetically sealed lid.

For preservation of samples, use 1 ml of 10% potassium dichromate solution or 1-2 drops of 40% formalin solution per 100 ml of milk.

Organoleptic study of milk

Taste and smell(GOST 28283-89). The assessment of taste is carried out selectively after boiling the sample, and the assessment of the smell in 10-20 ml of milk heated to 35°C.

Determination of appearance, color and consistency is carried out according to GOST R 52054-2003

Milk color determined in daylight in a colorless glass cylinder.

Consistency milk is determined by pouring a sample of milk into a cylinder of colorless glass. Cow's milk should be a thick homogeneous liquid without sediment and clots. Milk from cows with mastitis may have a slimy consistency and contain clots and flakes. Clots and flakes can form in sour milk, as well as in the rapid cooling of full-fat milk. In order to find out the reason for the formation of flakes and clots, the milk is heated to 30-40˚C. at the same time, flakes of fat, unlike mastitis, dissolve.

Organoleptic indicators of milk, depending on its variety, are presented in Table. 1, organoleptic defects of milk and the reasons for their appearance are presented in table. 2.

table 2

Organoleptic defects of milk

color flaws

dilution with water, fat removal, udder tuberculosis, storage in zinc dishes, pigment-forming microorganisms, feeding a large number of herbs containing blue pigment (water pepper, forget-me-not, etc.)

streptococcal mastitis, colostrum admixture, feeding a large number of herbs containing yellow pigment (bison, ranunculus, alfalfa)

Smell vices

Ammonia

Drug

and chemical

Rancid

Alcoholic

Musty and putrid

Storage of milk in an open container on a farm, bacteria of the E. coli group.

The use of drugs, when treating dairy cows, the joint storage of milk drugs or chemicals

Butyric fermentation

Alcoholic fermentation during storage of contaminated milk at low temperature

Putrefactive and anaerobic bacteria in tightly sealed uncooled milk.

Defects of taste

stern

Metal

Feeding cows with fishmeal, algae

Excessive feeding of cows with silage, haylage, root crops.

Old cow milk, colostrum, mastitis, tuberculosis

Storage of milk in tinned and rusty dishes and tinned dishes.

Eating horsetail, adding soda, udder tuberculosis, storing unrefrigerated milk in a closed container

Consistency defects

Foamy

watery

mucous

curdled

Yeast, E. coli, butyric fermentation

Dilution with water, feeding with watery feed (bard, root crops, silage, etc.), catarrhal mastitis, tuberculosis, estrus.

Mucus-forming bacteria, foot-and-mouth disease, colostrum, mastitis

Souring of milk, mastitis.

Determination of physico-chemical parameters of milk

In each batch of milk, the following laboratory parameters are determined: titratable acidity, temperature, mass fraction of fat, density or freezing point, purity group and heat resistance group. At least once a decade in the milk under study, the following is determined: bacterial contamination, the content of somatic cells and the presence of inhibitory substances, and the protein content is determined 2 times a month. If it is suspected that milk has been subjected to heat treatment, the presence of alkaline phosphatase in milk is checked. According to the results of organoleptic and laboratory studies, milk is divided into the highest, first, second grade and non-grade (Table 4).

Determination of milk temperature (GOST 26754-65)

The method of measuring the temperature of milk with a glass liquid (non-mercury) thermometer is based on the change in the volume of liquid in a glass shell depending on the temperature of the medium being measured.

The temperature of milk is measured directly in the tank, flask, bottle, package. When milk is received directly at farms, the temperature is measured in transport containers immediately after they are filled. Before measuring the temperature, milk in tanks and flasks is mixed.

To measure the temperature of milk, glass liquid thermometers are used in a frame according to GOST R 51652-2000. The thermometer is immersed in milk to the lower digitized mark and kept for at least 2 minutes. Readings are taken without removing the thermometer from the milk.

When measuring the temperature of milk with a glass liquid (non-mercury) thermometer, the result of the thermometer reading is rounded off to the nearest whole number. And the results of digital thermometers are determined according to the readings of the digital display of the measuring unit with an accuracy of 0.1˚С.

The arithmetic mean of the measurements is taken as the final result of measuring the temperature of milk in flasks and consumer containers.

Determination of titratable acidity of milk (GOST 3624-92)

The acidity of milk is due to the presence of lactic and other acids in it. The method is based on the neutralization of the acids contained in the product with sodium hydroxide solution in the presence of the phenolphthalein indicator.

In a flask with a capacity of 100 to 250 cm 3, 20 ml of distilled water, 10 ml of analyzed milk, and three drops of 1% phenolphthalein solution are measured. When analyzing sour cream, cream, cottage cheese, 5 g of the test product and 30-40 ml of distilled water (50 ml of warm water for cottage cheese) and three drops of 1% phenolphthalein solution are placed in a flask. The mixture is thoroughly mixed and titrated with 0.1 N. sodium hydroxide solution until a faint pink color appears, for milk and cream, corresponding to the control color standard, which does not disappear within 1 min.

To prepare a control standard. In a flask with a capacity of 100 or 250 cm 3, 10 ml of milk (5 g of dairy products) and 20 ml for milk (30-50 ml for dairy products) of distilled water and 1 cm 3 of a 2.5% solution of cobalt sulfate are measured. The mixture is thoroughly mixed. The shelf life of the standard is not more than 8 hours at room temperature.

The acidity of milk and dairy products in Turner degrees is the amount of 0.1 N. solution of sodium hydroxide, necessary to neutralize the acids contained in 100 g of the test product.

The calculation of milk acidity is calculated by the formula: К˚T=V 10,

acidity of dairy products К˚T=V 20

where: V is the amount of 0.1 n. solution of sodium hydroxide used to neutralize acids.

Determination of milk density (GOST 3625-84)

A sample with a volume of 0.25 or 0.50 dm 3 is thoroughly mixed and carefully, in order to avoid the formation of foam, is poured along the wall into a dry cylinder, which should be kept in a slightly inclined position. If foam has formed on the surface of the sample in the cylinder, it is removed with a stirrer. The cylinder with the test sample is installed on a flat horizontal surface, the temperature of the sample is measured. The reading of the temperature readings is carried out no earlier than 2-3 minutes after the thermometer is lowered into the sample.

A dry and clean hydrometer (lactodensimeter) is slowly lowered into the test sample, immersing it until 3-4 mm remains to the expected mark of the hydrometer scale, then leaving it in a free floating state. The device must not touch the walls of the cylinder.

Table 3

Density reduction cow's milk To20°C.

The location of the cylinder with the sample on a horizontal surface should be, in relation to the light source, convenient for reading the readings on the density scale and the thermometer scale. The first reading of the density readings is carried out visually from the hydrometer scale after setting it in a stationary position. After that, the hydrometer is carefully raised to the level of the ballast in it and lowered again, leaving it in a free floating state. After establishing it in a stationary state, a second reading of the density readings is carried out. When reading the density reading, the eyes should be at the level of the meniscus. The readings are taken along the upper edge of the meniscus (see Fig. 1).

Reading of indications on hydrometers of types AM and AMT is carried out up to half of the scale division value. In hydrometers of types AON-1 and AON-2, readings are counted up to the price of the name of the division. The temperature of the sample is then measured.

Measurement of sample temperature when using hydrometers of types AM, AMT, AO, AON-2 is carried out using mercury and non-mercury glass thermometers.

The arithmetic mean of the results of two indications is taken as the average value of the temperature and density of the test sample.

Measurement of the density of milk is carried out at a temperature of 15-25ºС. If the sample during the determination of the density had a temperature above or below 20°C, the results of the determination of the density should be reduced to 20°C in accordance with the data in table. 3.

Determination of milk purity group (GOST 8218-89)

The determination of the milk purity group is carried out using a device for determining the purity of milk with a filter surface diameter of 27-30 mm (Record or others) and filters made of needle-punched thermally bonded fiber.

The filter is inserted into the device with the smooth side up. Take 250 ml. thoroughly mixed milk heated to 35 ° C and pour it into the vessel of the device. At the end of filtration, remove the filter, put it on a sheet parchment paper and compare it with a standard. Milk is divided into 3 groups according to purity (see Table 4).

Table 4

Comparison sample for determining the purity group of milk

(when filtering a sample with a volume of 250 cm 3)

Determination of the mass fraction of fat in milk (GOST 5867-90.

Determination of fat content. In a clean milk butyrometer (butyrometer), without wetting the neck, pour 10 ml of sulfuric acid (density 1810-1820 kg / m 3) into a dispenser and, carefully so that the liquids do not mix, add 10.77 ml of milk with a pipette, attaching its tip to the wall of the neck butyrometer at an angle (the level of milk in the pipette is set at the lower level of the meniscus). Blowing milk out of a pipette is not allowed. Then 1 ml of isoamyl alcohol (density 810-813 kg/m 3 ) is added to the butyrometer with a dispenser. To determine the fat content of dairy products, the fat content of which is higher than in milk, a cream butyrometer is used, into which 5 g of sour cream, cream and cottage cheese or 2 g of butter are added, after which sulfuric acid and isoamyl alcohol are added.

Butyrometers: a) - milk b) - cream

The butyrometer is closed with a dry rubber stopper, introducing it a little more than half into the neck, turned over 4-5 times until the protein substances are completely dissolved and evenly mixed (the butyrometers should be wrapped with a napkin or towel when turning), after which they put the stopper down for 5 minutes in a water bath with a temperature of 65 ± 2 °C. Having taken out of the bath, the butyrometers are inserted into the cartridges (glasses) of the centrifuge with the working part towards the center, placing them symmetrically one against the other.

With an odd number of butyrometers, a butyrometer filled with water is placed in the centrifuge. After closing the centrifuge lid, the butyrometers are centrifuged for 5 minutes at a speed of at least 1000 rpm. Then each butyrometer is removed from the centrifuge and the movement of the rubber stopper adjusts the column of fat in the butyrometer so that it is in the tube with a scale. The butyrometers are then re-immersed, caps down, in a water bath at 65 ± 2°C.

Rice. 3 Automatic pipette for a set of sulfuric acid.

Automatic pipette for a set of sulfuric acid.

After 5 minutes, the butyrometers are removed from the water bath and the fat is quickly read. To do this, the butyrometer is held vertically, the border of fat should be at eye level. By moving the plug up and down, the lower limit of the fat column is set on the whole division of the butyrometer scale and the number of divisions is counted from it to the lower level of the meniscus of the fat column. The interface between fat and acid should be sharp, and the column of fat should be transparent.

The butyrometer readings correspond to the percentage of fat in milk. The volume of 10 small divisions of the milk butyrometer scale corresponds to 1% fat in the product. Fat counting is carried out with an accuracy of one small

dividing the butyrometer. The discrepancy between parallel determinations should not exceed 0.1% fat. The arithmetic mean of two parallel determinations is taken as the final result.

Determination of the freezing point of milk (GOST 30562-97)

This technique allows you to determine the presence of foreign water in the milk.

The thermistor cryoscopic method is used to determine the freezing point of milk.

The essence of the method is that the milk sample is cooled to a predetermined temperature (depending on the device), crystallization is caused by mechanical vibration, after which the temperature is quickly raised to a plateau, which corresponds to the freezing point of the sample.

The cryoscope consists of a thermally controlled cooling bath, a thermistor probe (semiconductor thermistor) with a preset circuit and a galvanometer or digital indicator, a sample stirrer and a crystallization trigger, and sample tubes.

Pour or pipette a test milk sample in the amount of (2.5 ± 0.1) cm 3 into a clean, dry sample tube. Make sure the probe and stirring wire are clean and dry (if necessary, wipe with a soft, clean, lint-free cloth).

Insert a test tube into a calibrated cryoscope. The milk is cooled and crystallized at the set temperature with an accuracy of 0.1 °C. (In some automatic instruments, the temperature can be observed on a digital scale; in other instruments, the necessary accuracy of inducing crystallization is ensured when the galvanometer needle coincides with the appropriate mark).

Determination of milk solids (SOM) and

dry skimmed milk residue (SOOM)

COM% \u003d 4.9 W% + P ° A + 0.5

SOM% \u003d SOM% -W%

where: F% - fat content of milk in%

P ° A - density in hydrometer degrees

(eg density 1028 kg/m 3 =28°A).

Normally, SOM of milk is from 11% to 17%, SOM > 8%.

Determination of heat stability of milk and cream with fat content

up to 40%by alcohol test(GOST 25228-82)

The method is based on the effect of ethyl alcohol on milk and cream proteins, which are completely or partially denatured when equal volumes of milk or cream are mixed with alcohol. To determine the heat resistance of the alcohol sample, milk is examined at a temperature of (20 + 2) ° C, and the cream is heated in a glass in a water bath to a temperature of up to (43 ± 2) ° C, mixed and cooled to a temperature of (20 ± 2) ° C.

The thermal stability of milk and cream according to the alcohol test is determined using an aqueous solution of ethyl alcohol with a volume fraction of ethyl alcohol of 68, 70, 72, 75 and 80%.

The density of water-alcohol solutions used for the alcohol sample, kg/m3, at (20.0 ± 0.1) °C should be equal to: for 68% volume fraction of alcohol; for 70% alcohol by volume; 880.5 for 72% alcohol by volume; 872.8 for 75% alcohol by volume; 859.3 for 80% alcohol by volume.

Pour 2 ml of the investigated milk or cream into a clean, dry Petri dish, add 2 ml of ethyl alcohol of the required volume fraction, mix thoroughly in a circular motion. After 2 minutes, observe the change in the consistency of the analyzed milk or cream.

Reaction accounting. If flakes did not appear on the bottom of the Petri dish when the analyzed mixtures of milk or cream with alcohol drained, it is considered that they withstood the alcohol test.

Depending on which solution of ethyl alcohol did not cause the precipitation of flakes in the tested milk and cream, they are divided into groups indicated in Table. 5.

Table 5

Milk heat resistance groups

Determination of the mass fraction of protein and mass fraction of total nitrogen (GOST 23327-98)

The Kjeldahl method is based on the mineralization of a milk sample with concentrated sulfuric acid in the presence of an oxidizing agent, an inert salt - potassium sulfate and a catalyst - copper sulfate. In this case, the amino groups of the protein are converted into ammonium sulfate dissolved in sulfuric acid.

The mass fraction of nitrogen in this solution is measured by one of the following methods:

chemical - by alkalizing the solution, distilling ammonia with steam, absorbing it with a solution of boric acid and titrating the latter with a solution of hydrochloric acid with indication of the equivalence point by changing the color of the indicator (manual titration) or using a potentiometric analyzer (manual or automatic titration) ;

electrochemical - by automatic coulometric titration of ammonia directly in the mineralized sample.

The mass fraction of the protein is determined by multiplying the result obtained by the corresponding coefficient.

Taking measurements

Several pieces of glass tubes are placed in a Kjeldahl flask or a test tube, and 10 g of a mixture of salts is added, 1 ml of a pre-weighed product is added, 10 cm 3 of sulfuric acid and 10 cm 3 of hydrogen peroxide or 0.5 g of potassium permanganate are added, after which they are heated on an electric stove until the contents stop violently foaming and until the liquid becomes clear and colorless or slightly bluish. Then the Kjeldahl flask or test tube is cooled to room temperature and the mass fractions of total nitrogen are determined chemically or electrochemically with the indication of the equivalence point.

Chemical way. The mineralizate in a Kjeldahl flask or test tube is dissolved in 20 cm 3 of distilled water and attached to a distillation apparatus (see Fig. 4 (1 - tile, 2 - flask with water, 3 - separating funnel, 4 - drop catcher, 5 - quartz test tube 6 - refrigerator 7 - receiving flask)). In a conical flask with a capacity of 250 cm 3, a 20 cm 3 mixture of a boric acid solution with an indicator solution is measured with a measuring cylinder and placed under a refrigerator for a boric acid solution with an indicator solution (methylene blue or brilliant green). Measure with a graduated cylinder 50 cm 3 of sodium hydroxide solution and carefully, avoiding emissions, pour it through a separating funnel into a Kjeldahl flask or test tube. The faucet of the funnel is immediately closed. Close the clamp on the steam outlet line and open the clamp on the steam supply line from the vaporizing flask to the Kjeldahl flask or test tube. The distillation is carried out until the volume of the condensate reaches 90 - 120 cm 3 (distillation time - 5-10 minutes).

Table 6

Changing the color of a solution during titration

with various indicators

The contents of the conical flask with a solution of the indicator, boric acid and condensate is titrated with a solution of hydrochloric acid with a concentration of 0.2 mol/DM 3 until the color changes indicated in table. 6.

In parallel, put a control reaction without milk.

Processing of measurement results

The mass fraction of total nitrogen X% is calculated by the formula:

X% \u003d 1.4 (V-V 1) C

where: V is the volume of acid used for titration, cm3;

V1 - the volume of acid spent on titration during the control measurement, cm 3

C - concentration of hydrochloric acid, mol / dm 3

m is the weight of the sample of the product, g;

1.4 - coefficient for converting the volume of acid into the mass fraction of total nitrogen

Mass fraction of protein Y%, determined by the formula

electrochemical method. After cooling, the mineralizate is quantitatively transferred into a volumetric flask with a capacity of 50 cm 3, the volume of the solution is adjusted to the mark with distilled water and mixed.

0.2 cm 3 of a neutralizing solution is added to the measuring cell of the titrator filled with an anode solution (100 g of potassium bromide and 240 g of sodium hydroxide are dissolved in 1 liter of distilled water), and then 0.1 cm 3 of the mineralizate solution and the button is turned on "Start" automatic titration. The process of titration of ammonia is carried out automatically. At the end of the process, the device turns off. The readings of the digital indicator correspond to the value of the mass of total nitrogen in the sample.

Determination of the mass fraction of moisture in butter.

An empty weighing bottle is weighed on an analytical balance with an accuracy of 0.001 g, then a weighing of about 5 g of butter is placed in the weighing bottle and reweighed. After weighing, the bottle with butter is heated over the flame of a burner or on an electric stove until all moisture has evaporated from it (boiling oil will begin to turn brown, stop crackling and water bubbles will disappear in it). After heating, the bottle with oil is re-weighed and the mass fraction of moisture is calculated using the formula:

X%=(M-M1) 100%

X% - mass fraction of moisture

M is the mass of the bottle with oil before evaporation of moisture in g.

M1 is the mass of the bottle with oil after evaporation of moisture in the city of

A is the mass of oil in g.

Determination of the main microbiological indicators of milkDetermination of the total microbial contamination of milk

The total microbial contamination of milk is one of the most important indicators of milk safety. There are two ways to determine the total microbial contamination, direct and indirect.

Determination of the total microbial contamination of milk by direct seeding. Sequential dilutions are prepared from a milk sample in sterile 0.9% NaCl solution from 1:10 to 1:1,000,000. From the last three dilutions, I do 2-3 inoculations (1 ml) in Petri dishes and fill them with melted meat-peptone agar or a special medium. Seeded cups are placed in a thermostat at 37°C for two days when seeded on MPA or at 33°C for 72 hours (special medium). The number of grown colonies is multiplied by the dilution, then the arithmetic mean is calculated, resulting in the number of microbial cells in 1 ml of milk.

Determination of reductase in milk (indirect method). The method is based on the reduction of resazurin and methylene blue by redox enzymes (reductase) secreted into milk by microorganisms. The duration of the color change evaluates the bacterial contamination of raw milk.

Reaction with methylene blue. 1 ml of a working solution of methylene blue (0.0015%), which is prepared from the main solution (0.005%) and 20 ml of the test milk, is poured into a sterile test tube, closed with a cork, mixed by slowly turning the test tube three times and placed in a reducer with a water temperature of 37 -38°С.

In the absence of a reducer, a water bath at a temperature of 37-38°C can be used. The water in the reducer or water bath after immersing the test tube with milk should reach the level of the liquid in the test tube or be slightly higher.

The moment the tubes are immersed in the reducer is considered the beginning of the analysis. Observation of the color change is carried out after 40 minutes, 2.5 hours and 3.5 hours minutes after the start of the analysis. The end of the analysis is considered the moment when the color of the milk becomes discolored, while the remaining small annular colored layer at the top (about 1 cm) or at the bottom of the tube is not taken into account. The appearance of coloring of milk in these test tubes during shaking is not taken into account.

Depending on the time of discoloration, milk is classified into one of four classes according to the degree of its good quality and the approximate bacterial contamination is determined by the number of microorganisms that produce reductase (see Table 7).

Table 7

Accounting for the reaction with methylene blue

Reaction with resazurin. 1 ml of the working solution (0.014%) of resazurin, which is prepared from the main solution (0.05%) and 10 ml of the test milk, is poured into a sterile test tube, closed with a cork, mixed by slowly turning the tube three times and placed in a reducer with a water temperature of 38-40 °C. Accounting for the reaction is carried out after 1 hour and 1.5 hours by color change (see table. 8).

Table 8

Accounting for the reaction with resazurin

Definitions of coli-titer of milk

Coli titer is the smallest amount of milk that contains one bacterium of the Escherichia coli group.

Coli-titer is an important microbiological indicator reflecting the hygiene of milk production.

The minimum allowable coli-titer values for: raw milk - 0.1 ml, for pasteurized draft milk - 0.3 ml, for pasteurized milk packed in consumer containers - 3 ml.

To determine the coli-titer from a sample of raw milk, serial dilutions are prepared in sterile 0.9% NaCl solution from 1:10 to 1:100,000. Then inoculate from each dilution (1 ml) into a test tube with Kessler's medium (lactose and gas). To determine the coli-titer of pasteurized milk in 3 test tubes with Kessler medium

Table 9

Determination of coli-titer of raw milk

Amount of milk in a test tube					Coli-titer
					Coli-titer

Table 10

Determination of the coli-titer of pasteurized milk

Amount of milk in a test tube						Coli-titer
						Coli-titer

inoculate 1 ml of milk and inoculate three test tubes from a dilution of 1:10.

Accounting for the growth of Escherichia coli is carried out by the presence of carbon dioxide in the gas.

Determination of if the titer is carried out according to the table. 9, 10.

Determination of somatic cells in milk (GOST 23453-90)

The method is based on the interaction of the drug "Mastoprim" with somatic cells, as a result of which the consistency of milk changes.

Analysis. 1 ml of thoroughly mixed milk is added to the well of the PMK-1 plate and 1 ml of an aqueous solution of the Mastoprim preparation is added. Milk with the drug is intensively mixed with a wooden, plastic or glass rod for 10 s. The resulting mixture from the well of the plate is lifted with a stick up by 50-70 mm with continuous intensive stirring, after which the results of the analysis are evaluated for no more than 60 s.

Processing of results The number of somatic cells in the test milk is determined by the consistency of the milk.

1. Homogeneous liquid or weak clot, which slightly stretches for a stick in the form of a thread up to 500 thousand times.

2. A pronounced clot, when stirred, a notch at the bottom of the hole of the plate is clearly visible. The clot is not ejected from the hole from 500 thousand to 1 mil.

3. A dense clot that is ejected with a stick from the hole of the plate over 1 mil.

For more exact definition somatic cell counts using a viscometer.

Determination of the quality of milk pasteurization (GOST 3623-73)

The sale of raw milk in the distribution network is prohibited, therefore milk is subjected to heat treatment at dairies. Raw milk must be delivered to dairies. Pasteurization is one of the most common heat treatment methods for milk. Pasteurization reduces the overall microbial contamination of milk by more than 90%, while milk retains most of the vitamins, enzymes and other useful biologically active substances.

In Russia, the following temperature regimes are used for pasteurization:

Low temperature pasteurization 63°C 30 minutes or 72°C 20 seconds.

High temperature pasteurization 75°C 10 minutes, 80°C 30 seconds or 85°C without holding.

During low-temperature pasteurization, alkaline phosphatase is destroyed in milk, and during high-temperature pasteurization, the peroxidase enzyme is destroyed. Therefore, the presence of these enzymes in pasteurized milk indicates that pasteurization was carried out incorrectly.

Determination of peroxidase by reaction

with potassium iodide starch

The essence of the method. The method is based on the decomposition of hydrogen peroxide by the enzyme peroxidase contained in milk and dairy products. Active oxygen released during the decomposition of hydrogen peroxide

oxidizes potassium iodide, releasing iodine, which forms a blue compound with starch.

Preparation of potassium iodide starch. 3 g of starch is weighed with an error of not more than 0.01 g and mixed with 5-10 cm 3 of distilled water. cold water until a homogeneous mass is obtained. Separately, in a flask, bring to a boil 100 cm 3 of distilled water and, with continuous stirring, add water to the diluted starch, preventing the formation of lumps. The resulting solution is brought to a boil. After cooling, 3 g of potassium iodide is added to the starch solution, stirring until the potassium iodide crystals dissolve.

A solution of potassium iodide starch is an unstable reagent, so it should be prepared in small quantities and stored in a dark, cool place for no more than two days.

Reaction setting. In a test tube with 5 ml. milk, 5 drops of a solution of potassium iodide starch and 5 drops of a 0.5% solution (2 drops of 1% solution) of hydrogen peroxide are added, the contents of the test tube are mixed with rotational movements after adding each reagent. The presence of peroxidase is then determined by the color change.

If a solution of starch and potassium iodide is used separately, then proceed as follows: 0.5 cm 1% starch solution, 2 drops of 10% potassium iodide solution and 5 drops of 0.5% hydrogen peroxide solution, mix the contents of the test tubes after adding each reagent, then determine the presence of peroxidase by color change.

Evaluation of results. In the absence of the peroxidase enzyme in milk and dairy products, the color of the contents of the tube will not change. Therefore, milk and dairy products were pasteurized at a temperature not lower than 80°C.

In the presence of peroxidase in milk, cream, butter, the contents of the test tubes acquire a dark blue color.

The sensitivity of the method makes it possible to detect the addition of at least 5% of unpasteurized dairy products to pasteurized ones.

Determination of the presence of alkaline phosphatase in milk

The method is based on the hydrolysis of the disodium salt of phenylphosphoric acid by the enzyme phosphatase contained in milk and dairy products. The free phenol released during hydrolysis in the presence of an oxidizing agent gives a pink color with 4-aminoantipyrine.

Preparation of solution A. 1.25 g of the disodium salt of phenylphosphoric acid is weighed with an error of not more than 0.0002 g, dissolved in 100 cm 3 of the main buffer solution (to 348 ml of 25% ammonia solution add 40 g of ammonium chloride, previously dissolved in 100 ml of distilled water, and dilute to 1 liter with distilled water).

Preparation of solution B. 0.8 g of 4-aminoantipyrine, weighed with an error of not more than 0.0002 g, is dissolved in 900 cm 3 of distilled water.

Solutions A and B should be colorless and stored in dark glass bottles in the refrigerator. Shelf life no more than 1 month. Yellowed solutions are unsuitable for work.

The working solution of the substrate is prepared immediately before determining the reaction by mixing solutions A and B (1:9). The working solution is suitable for work for 8 hours when stored in a dark glass bottle.

Preparation of the precipitant of the zinc-copper system. 30 g of zinc sulfate heptahydrate and 6 g of copper sulfate pentahydrate, weighed with an error of not more than 0.01 g, are dissolved in 1 liter of distilled water.

Analysis To 3 cm 3 of milk, add 2 cm 3 of the working solution of the substrate. Then the contents of the tube are mixed and placed in a water bath heated to 40-45 °C for 30 minutes. Add 5 cm3 of a zinc-copper system precipitant to a test tube taken out of a water bath, thoroughly mix the contents of the test tube and place it again in a water bath at a temperature of 40-45ºС for 10 minutes. After removing the test tube from the bath, a visual comparison is made between the contents of the tube of the test product and the control experiment.

A similar reaction with boiled milk is used as a control.

In the absence of the phosphatase enzyme in milk and dairy products, the color of the contents of the tube (solution separated from the precipitated protein) is colorless, i.e., similar to the contents of the test tubes of the control experiment. Therefore, milk and dairy products were pasteurized at a temperature not lower than 63ºС.

Determination of phosphatase by reaction

with sodium phenolphthalein phosphate

The essence of the method. The method is based on the hydrolysis of sodium phenolphthalein phosphate by the enzyme phosphatase contained in milk and dairy products. The phenolphthalein released during hydrolysis in an alkaline medium gives a pink color.

Reaction setting. 2 ml of milk, 2 ml of distilled water and 1 ml of sodium phenolphthalein phosphate in ammonia buffer are measured into a test tube. After that, the contents of the tube are stoppered, shaken and placed in a water bath. The contents of the tube are evaluated after 10 minutes and after 1 hour.

In the absence of the enzyme phosphatase in milk and dairy products, the color of the contents of the test tube does not change. Therefore, milk and dairy products were pasteurized at a temperature not lower than 63ºС. In the presence of phosphatase in milk and dairy products, the contents of the test tube acquire a color from light pink to bright pink. Therefore, milk and dairy products have not been pasteurized, or have been pasteurized at temperatures below 63°C, or have been mixed with unpasteurized products.

The sensitivity of the method makes it possible to detect the addition of at least 2% of unpasteurized dairy products to pasteurized ones.

Then the tube is placed in a water bath with a water temperature of 40 to 45ºС and the color is determined.

Determination of adulteration of milk and dairy products

Milk falsification can be natural or artificial. Natural falsification is understood as the intentional sale of mastitis milk, colostrum or milk obtained from sick animals. In case of artificial falsification, various substances are added to milk in order to increase its volume, the terms of implementation, the prevention of milk souring, etc.

Definition of falsification of milk by water.

To increase the volume of milk, it is diluted with water, while changing the organoleptic and laboratory parameters of milk. The taste and smell of milk of diluted milk are weakened, the consistency is liquid less viscous, the color is bluish, fat<3,2%, СОМ<11%, СООМ<8%, кислотность <16ºТ, плотность < 1027 кг/м.

Determination of the presence of inhibitory substances in milk

(GOST 23454-79)

To increase the shelf life of milk, it is falsified with inhibitory substances (antibiotics, sulfonamides, preservatives, and other substances that inhibit the growth of microflora).

Analysis. 10 cm 3 of the test milk are poured into sterile test tubes and closed with sterile rubber stoppers. The rest of the sample is stored until the end of the analysis in the refrigerator at a temperature of (6±2)°C.

Test tubes with test milk and a control sample are heated in a water bath to (87±2)ºС for 10 minutes, then cooled to (47±1)°С. Then, 0.5 cm 3 of the working test culture St. Termophilus, prepared from a collection test culture.

The contents of the test tubes are thoroughly mixed by inverting three times. Then the tubes are kept for 1 h 15 min at a temperature of (46 ± 1) °C in a reducer or water bath.

1 cm 3 of the main solution of resazurin with a temperature of (20 ± 2) ºС is introduced into the test tubes with the milk under study and the control sample. The contents of the test tubes are mixed by double inversion.

Test tubes with test milk and a control sample are kept in a reducer or a water bath with a thermostat or a water bath placed in a thermostat at (46±1)°C for 10 minutes.

Processing of results. In the absence of inhibitory substances in the test milk (and in the control sample), the contents of the test tubes will be pink or white.

In the presence of inhibitory substances in milk, the contents of the test tubes will have a color characteristic of class 1 milk according to the color scale for determining the class according to the reductase test with resazurin according to GOST 9225-84.

Determination of adulteration of milk with formalin

Place 1 ml of the test milk into a test tube and add 1 ml of Rigel's reagent (a mixture of concentrated sulfuric and nitric acids). In the presence of formalin in milk, a blue-violet ring is formed at the border of milk and Rigel's reagent.

Determination of adulteration of milk with hydrogen peroxide

GOST 24067-80

1 cm 3 of the investigated milk is placed in a test tube, without stirring, two drops of a sulfuric acid solution and 0.2 cm 3 of a 3% solution of potassium iodide starch are added.

After 10 minutes, observe the change in the color of the solution in a test tube placed in a tripod, avoiding shaking it.

The appearance of individual blue spots in the test tube indicates the presence of hydrogen peroxide in milk.

Definition of adulteration of milk

chrompic (potassium bichromate)

1 cm 3 of the investigated milk is placed in a test tube, 5-7 drops of 5-10% solution of silver nitrate are added. Mix the contents of the tube. If there is a chrompic in milk, it acquires a lemon-yellow or red-yellow color.

Determination of falsification of milk by soda.

To prevent souring of milk and dairy products, they are adulterated with soda.

Soda does not dissolve well in milk, so grains of undissolved soda can be found at the bottom of the container.

The admixture of soda in milk and dairy products is determined by adding a few drops of a 0.2% alcoholic solution of rosolic acid to 3-5 ml of the investigated milk or dairy product. In the presence of soda, the contents in the test tube turn pink-red, and in the absence - in orange.

When adding 7-8 drops of alcohol 0.04% solution of bromthymol blue to 5 ml of milk, milk with soda turns dark green, green-blue or blue; without soda - in yellow or salad color.

Determination of adulteration of milk by starch

The falsification of milk, sour cream, cream with starch is determined by adding 2-3 drops of Lugol's solution to a test tube with 5 ml of well-mixed milk (sour cream, cream). The contents of the tube are thoroughly shaken. The appearance of a blue color after 1-2 minutes indicates the presence of starch in the test sample.

Definition of adulteration of sour cream

yogurt or cottage cheese

In a glass of hot water (66-75 ° C), stir one teaspoon of sour cream. If cottage cheese is added to the product, then it settles to the bottom. Pure sour cream does not give sediment.

I am a big fan of all sorts of quality checks and examinations of various food products, as I monitor my health and try to eat only high-quality food. Moreover, I am always worried about the question: what kind of food can be given to children? I accidentally got on the website of Roskontrol, which conducts an independent examination of products, and spent half the night on it - until I was convinced that everything I eat was safe, I did not calm down. Although, after reading their results of the examination of food products, I will now change some brands of products in my grocery basket.

I will say right away that some results of food examinations surprised me a little and I would even doubt whether some brand paid for the promotion of its brand, but the site contains scans of documents from experts with seals, and often even a video of how an independent examination took place, so the results are to be trusted. Although it is not easy to realize that the cheapest Dixy water, for example, is better than all popular brands. And in the well-known water "Arkhyz" they found Pseudomonas aeruginosa and twenty times the norm of microbes, and so on ... unexpectedly! All in all, very useful research!

As for the organization. According to the website: “Roskontrol is a non-profit partnership that brings together leading research laboratories and scientific institutions in Russia….

Methods for checking and rating products are based on Russian state and international standards. The most authoritative testing laboratories and expert organizations are involved in conducting research and examinations ... ”Well, further on the site is a list of reputable scientific institutions that conduct independent examinations of food products.

For those who have no time to study all the examinations, I decided to go through their tests and write in a simple list what you can eat, what you shouldn’t, and what is generally dangerous and blacklisted. The company sues those manufacturers whose products do not meet quality standards and are recognized by the expert examination as dangerous. Well, now you are more attentive to the choice of products and brands and brands.

Since there are a lot of tests, this article will results of examination of dairy products. Although I make kefir and cottage cheese on my own, and also cook homemade cheese with my own hands and advise you, this is in any case very, very necessary information. In the near future I will do such reviews for all other products.

zucchini zucchini

For those who are interested, you can also read my nitrate tests:
The content of nitrates in vegetables, fruits and meat in Auchan
Checking products for nitrates with a Soeks nitrate meter in Dixy
Checking products with a nitrate meter in the Polushka store

So! Which foods should not be eaten categorically, and which ones have passed all the checks and examinations of food products!

From top to bottom - the higher the product in the list, the more points it scored in terms of quality and taste.

Examination of dairy products

good milk

Expertise of MILK

Milk that has passed quality control:

"Ruzskoye", 3.2-4%, pasteurized whole
"Avida", 3.2%, pasteurized
Mamulya, 3.2%, UHT
"House in the village", 3.5%, whole pasteurized
Vologzhanka, 1.5%, pasteurized
"Vkusnoteevo", 3.2%, pasteurized
Prostokvashino, 3.5%, whole pasteurized
Dmitrov Dairy Plant, 3.2%, pasteurized

bad milk

It is better not to use milk of these brands, a product with violations, not safe, etc.:

Svitlogorye, 3.2%, pasteurized
"Our milking milk", 3.5%, whole
"Tevye milkman", 3.4-4.0%, pasteurized

This milk is blacklisted!!! Drinking such milk can be life threatening!

"Molti" 3.2%, pasteurized
"Milava", 3.2%, pasteurized

good kefir

KEFIR Expertise

Fortunately, kefir, which was tested for quality, passed the tests.

Kefir, which has passed the examination:

And again from top to bottom from those that scored more points for quality
Kefir BioMax, 1%
Kefir "Ruzsky", 3.2-4%
Fermented milk product "Vkusnoteevo", 1%
Kefir "House in the village", 1%
Kefir "36 kopecks", 3.2%
Kefir Prostokvashino, 1%
Kefir product "Activia", 1%

good cottage cheese

Examination of cottage cheese

Curd that has passed quality control

"Vkusnoteevo", 9%
"Clean Line", 9%
President, 9%

Bad curd

But cottage cheese, which the results of the examination recognized as dangerous! These brands of cottage cheese are on the black list!!!

Prostokvashino, 9%
Dmitrovsky Dairy Plant, 9%
"Dmitrogorsky", 9%
Ostankinskoye, 9%
"House in the village", 9%
Ruzsky, 9%
"B.Yu. Aleksandrov", 9%

good oil

Examination and quality control of BUTTER:

Butter quality examination recognized as good butter:

"From Vologda", 72.5%, peasant
Milkmaid, 82.5%
"From Vologda", 82.5%, Vologda
Lurpak, 82%
Ruzskoe, 82.5%
Anchor, 82%
Valio 82%

bad oil

But the oil, which is recognized as dangerous and blacklisted:

Ecomilk, 72.5%
Dmitrovsky Dairy Plant, 82.5%

good cheese

CHEESE expertise

Checking the cheese showed us which cheese is of good quality:

"Thousand Lakes", creamy
"City of Cheese", Russian
Epiim, Estonian
"ProstoSyr", Russian
Mlekpol, Russian
"Red Price", Russian
"Svalya"
Kiprino, Soviet
"Savushkin Product", Dutch