Milk from cows from disadvantaged settlements for various infectious and especially dangerous diseases, as well as those vaccinated against anthrax and foot and mouth disease for 2 weeks, sick with mastitis, endometritis, gastroenteritis and other diseases, is not allowed for sale in the markets. Milk from cows also does not go into sale in the first 7-10 days after calving and in the last 7-10 days before starting.

The sale of milk and dairy products on the market prior to the HSE is not allowed.

Milk entering the market from farms unfavorable for infectious diseases is tinted with cocoa, coffee, food paint, seized and disposed of under the supervision of the veterinary service in the presence of a representative of the farm or owner, about which an act is drawn up in 2 copies, one of which is issued to the owner, the other remains in the LANSE of the market.

It is prohibited to sell milk and dairy products with the following falsification: milk - when removing fat, adding water, starch, soda and other impurities; sour cream and cream - an admixture of cottage cheese, starch, flour, kefir; butter - an admixture of milk, cottage cheese, lard, cheese, potatoes, vegetable fats; varenets, fermented baked milk, yogurt - skimming, admixture of soda. Milk obtained from cows with an unknown etiology of the disease is not allowed for sale.

In the markets, it is allowed to sell milk (cow, goat, sheep) for signs of purity not lower than the second group, for bacterial contamination not lower than second class, and mare - 1st group for purity and 2nd class for bacterial contamination.

Persons selling milk and dairy products in the markets must have personal health certificates or certificates of passing medical examinations established for employees of food enterprises and observe the sanitary rules for trade in these products.

Before the start of the HSE of milk, the documents must be checked, they are registered in the journal. Then the veterinary specialist of GLVSE checks the cleanliness of the container. Does not allow for sale milk and dairy products in galvanized dishes and containers not approved by the State Sanitary and Epidemiological Supervision for the storage and transportation of milk and dairy products.

Milk samples are taken at least 250 ml, sour cream and cream - 15 ml, butter - 10 g, cottage cheese and feta cheese - 20 g, varenets, yogurt, fermented baked milk - 50 ml. the selected samples are examined in the laboratory no later than 1 hour after taking. At the same time, they must control organoleptic characteristics, purity, density and acidity; the primary milk is examined additionally for fat content. All results of veterinary sanitary examination of milk and dairy products are registered in the journal of form No. 24-vet.

VSE of milk provides for an assessment of its danger in an infectious relation, determination of falsification, organoleptic defects (change in color, consistency, the presence of impurities), acidity, content harmful substances... When examining milk, first determine its naturalness (conditionality) by organoleptic and physicochemical methods. At the same time, attention is paid to the purity and color of the product. Changes in color, taste, consistency of milk are observed in some diseases of the uterus and feeding the appropriate feed containing carotene and carotenoids. An admixture of flakes or clots in milk indicates a disease of the breast and the presence of certain defects in it.

Factors causing milk defects include: the physiological state of lactating animals, the disease of the animal, non-observance of the conditions of keeping and feeding, the unsatisfactory condition of livestock buildings, the poor condition of pastures, the introduction of drugs into the body, violation of the technology of primary milk processing, various falsifications, and other major defects associated with changes in the color, consistency, smell and taste of milk.

Cow's milk according to GOST 13264-88 must have the following indicators: density - 1.027 - 1.033 mg / cm3, protein - at least 3%, fat - at least 3.2%, acidity - 16-18T °, pH - 6, 65+ 0.2, somatic cells - up to 500 thousand in 1 ml.

Organoleptic characteristics of goat milk are close to cow's milk: fat - not less than 4.4%, density - 1.027-1.038, acidity - no more than 15T °.

Sheep's milk is white, fat must contain at least 5%, density - 1.034-1.038, acidity - 24T °.

Mare's milk is sweetish, tart with a bluish tinge: fat - more than 1%, density - 1.029-1.033, acidity - no more than 7T °.

Persons who sell milk not from cow, but from other animals must clearly indicate the type of milk for the buyer and observe the hygiene rules of trade in these products. The sale of mixed milk from different animals is not allowed.

Sour cream

When controlling sour cream, the type, uniformity, color, smell, taste, consistency, acidity (60-100T °), fat content (more than 25%), starch, cottage cheese, flour and other substances are checked. Sour cream should be clean, without foreign smell, thick, homogeneous, glossy, without grains of fat and casein. It is not allowed to sell sour cream with released whey, viscous, osmulaya, contaminated, with foreign odors and aftertaste, in a moldy container. Sour cream becomes bitter when long-term storage, with a metallic taste - from containers, greasy - from mold and added fats, viscous - from bacteria, swollen - from abnormal storage temperatures.

Have curd check the organoleptic indicators for homogeneity (no lumps, non-loose, non-crumbly), acidity (the norm is not higher than 240T °), falsification (soda, etc.). Cottage cheese is allowed for sale clean, delicate, without foreign tastes and odors, homogeneous, medium-sized and without lumps, white or yellowish. The purity and uniformity of the curd is determined in a special apparatus.

The curd is laid out in a thin layer in a Petri dish, placed on the substrate of the apparatus and pushed inside. Then the device is plugged into the network and the results are looked at: pure fresh cottage cheese made under normal conditions luminesces with a yellowish color, cottage cheese made from skimmed milk in a tin can in ultraviolet light glows with pure bright blue-purple; slightly polluted, with impurities - bluish-green; highly bacterially contaminated cottage cheese glows bright green with multi-colored spots - such cottage cheese is not released for sale. Organoleptic and physicochemical methods of milk research and fermented milk products in a special well-lit room, on a clean table covered with waterproof material. The color of milk is determined in a cylinder of colorless glass under reflected light, the consistency is determined by slowly pouring milk in a thin stream along the wall of the cylinder. The smell is checked at room temperature at the time of opening the vessel or when pouring milk heated to 40-50C °. The taste of milk is determined after boiling, while the milk is not swallowed, it just moistens the tongue.

Determination of milk purity. Mechanical contamination (purity) of milk is determined using devices with a filter plate diameter of 27-30 mm, paper, cotton filters or flannel. Take 250 ml of well-mixed milk with a measuring cup and pour it into a container. To accelerate filtration, milk is heated to 30C °. Depending on the amount of particles remaining on the filter, milk is divided into 3 groups according to the standard: 1 g .: there are no mechanical particles on the filter; 2 gr .: single particles on the filter; 3 gr .: a sediment of small and large particles (hair, sand, hay particles, etc.) is noticeable. After the filtration of milk is finished, the filters are placed on a clean sheet of paper and dried. Also, special attention is paid to identifying various falsifications. For this purpose, methods of researching milk and fermented milk products are used.

Determination of milk density. The density of milk is determined using hydrometers of the AMT type (with a thermometer) and AM (without a thermometer). The hydrometer is immersed in milk, carefully poured into the cylinder, so that it does not touch the wall. The numbers on the hydrometer scale increase from top to bottom, because as the density decreases, the instrument sinks deeper. The readings are taken into account no earlier than 1 min after the hydrometer is set in a stationary position, while the eye should be at the level of the milk surface. It is recommended to determine the density of milk at a temperature of 20C °.

When water is added, the density of the milk decreases. The addition of water to milk is determined by the dry matter content (below 8%); soda impurity - by mixing 3 - 5 ml of the product with 0.2% alcoholic solution of rosolic acid (pink-red color), or using bromothymolblau (dark green color); starch admixture - by adding 2-3 drops of lugol solution (blue color) to the product or the same amount alcohol solution iodine. The accuracy of determining the density of milk is influenced by the presence of mechanical impurities, analysis earlier than 2 hours after milking, excessively low or high temperature of the test milk, poor mixing or strong agitation, increased acidity, dirtiness of the hydrometer, touching the cylinder wall with the device.

Fat and somatic cell content in milk check using the device "CLOVER - 1M". The device is connected to the network, allowed to warm up for 3-5 minutes, after which they expect a characteristic sound signal, which means that the device is ready for operation. Thoroughly mixed milk in a volume of 20 ml is poured into a special container fixed on the device and the device is left in this state for 3-4 minutes. After this time has elapsed, the measurement results appear on the digital display of the device. First, the device gives data on the content of fat in milk, then the number of somatic cells and, as a result, the density.

The presence of somatic cells in milk is also determined using the Betta test. To do this, add 10 ml of milk with a syringe to a Petri dish, add an equal amount of the drug, mix well with a glass rod and record the result. Milk from a healthy cow should remain liquid, it does not stretch for the stick, the mass of the contents of the container is homogeneous.

To determine the protein content in milk, 10 ml of milk, 10-12 drops of a 1% alcoholic solution of phenolphthalein are poured into a flask, and 0.1 N is added dropwise. sodium hydroxide solution until a pale pink color appears, which does not disappear when shaken. Then add 2 ml of neutral (phenolphthalein) formalin and titrate with 0.1 N. sodium hydroxide solution until a pale pink color appears, which does not disappear within a minute. The amount of alkali used for titration after the addition of formalin is multiplied by a factor of 1.92 and the total protein content in milk is obtained, and by multiplying by a factor of 1.51, the casein content (in%) is determined.

Determination of acidity of milk... The acidity of milk is determined to establish its freshness by a titrometric method. 10 ml of milk is pipetted into a conical flask or cylinder with a capacity of 150-200 ml, 20 ml of distilled water, 3 drops of a 1% alcoholic solution of phenolphthalein are added. The mixture is thoroughly mixed and titrated from a burette with 0.1 N HCl. solution of sodium hydroxide (potassium) until a light pink color appears, which does not disappear within 1 min (according to the control standard). A control color standard is prepared immediately prior to analysis. For this purpose, 10 ml of milk, 20 ml of boiled distilled water and 1 ml of a 2.5% solution of cobalt sulfate are mixed in a conical flask with a capacity of 150-200 ml. The standard is suitable for work within 1 day of work. The acidity of milk in Turner's degrees (T °) is equal to the number of milliliters of 0.1 N. solution of sodium hydroxide (potassium), consumed for neutralization of 10 ml of milk, multiplied by 10. The discrepancy between repeated tests should not exceed 1T °. If necessary, the acidity of milk can be determined without adding water. The resulting acidity result is reduced by 2%.

6.WSE vegetable oil

Organoleptic examination of vegetable oils determines color, transparency, sediment, odor and taste. The taste of vegetable oils is evaluated at a temperature of 18 - 20 ° C. To determine the smell of oil, part of the sample or sample is heated to 45 - 50 ° C and smeared with a thin layer on a glass plate or glass slide. The color is assessed by examining the oil in the container, and to clarify it, it is preliminarily defended or filtered, after which it is poured into a beaker made of colorless glass and viewed in transmitted light against the background of a sheet of white paper. In the cold season, vegetable oils become cloudy due to crystallization of refractory fat fractions. For storage of oils, containers that meet sanitary requirements are used.

Sunflower oil. Good-quality sunflower oil should be transparent or with the presence of light turbidity, with a smell and taste characteristic of sunflower oil, without foreign smell, bitterness. The quality of the oil was determined by the reaction for peroxide with potassium iodide. 3 ml of oil is poured into a flask and a solution consisting of chloroform (7 ml), glacial acetic acid (5 ml) and a saturated solution of potassium iodide (1 ml) is added; then 60 ml of distilled water is poured, the mixture is shaken and its color is determined. The quality of the oil is assessed depending on the color of the mixture: good-quality oil - a mixture of straw-yellow and yellow, dubious quality - a mixture of yellow-brown color, sometimes with a pink tint, poor quality - a mixture of raspberry-red color.

7.WSE flour

Examining wheat flour. Sale of wheat, rye, corn flour is allowed. The sanitary assessment of the quality of flour is determined by the results of an organoleptic study (appearance, character of grinding, color, texture, smell and taste), and also depends on humidity, presence of impurities and infestation by various pests.

Organoleptic indicators. Good-quality flour should be evenly finely ground, dry to the touch, not lumpy; squeezed in a handful, it should crumble when unclenching the hand.

Colour flour is determined in daylight, for which 3 - 5 g of it is placed on black paper and lightly pressed with a glass plate. The color of flour depends on the type of raw material, the type and quality of grain, the way it is processed and the presence of impurities. Wheat flour should be white with a yellowish tinge, rye - grayish-white. Flour containing bran is darker in color.

Smell. 20 g of flour is placed on clean paper, warmed with breath and the smell is examined. To enhance the smell, flour is poured into a glass, poured with hot (60 ° C) water, shaken, the glass is covered with a glass plate and left for several minutes. Then the water is drained and the smell is determined. Good quality flour should not have a musty, sour, wormwood or any other foreign smell.

The taste and admixture of sand is determined by chewing about 1 g of a sample of flour. Good quality flour has a slightly sweet taste.

The presence of bitter, sour and other tastes unusual for good-quality flour, as well as sand or mineral impurities established when chewing, is not allowed.

Laboratory methods for the study of flour.

Determination of moisture content is carried out with doubtful indicators of organoleptic evaluation and carried out by drying a sample of flour (10 g) in an oven at a temperature of 130 ° C for 40 minutes, as specified in clause 4.2.1 of these Rules. The moisture content in flour should be no more than 15%.

Determination of barn pests is carried out by sifting at least 500 g of flour through a sieve with holes of no more than 1.5 mm. If mites, bugs and other pests are found in the residue on the sieve, as well as rodent droppings, the sale of flour is not allowed.

Determination of metallic impurities. A sample of flour is scattered in a thin layer on a sheet of paper or glass and carried out with a magnet 2-3 times in different directions. Before each such operation, the flour is mixed and again leveled with a thin layer. The collected metal impurities are weighed on analytical balance... It is forbidden to sell flour (cereals) if the content of dusty metal impurities is more than 3 mg per 1 kg of flour, as well as if metal particles are found.

8.WSE poultry

5 carcasses of a bird with a head and 7 without a head were delivered. Poultry carcasses are delivered to the market whole and only gutted with the internal organs separated (except for the intestines). Inspection of carcasses of chickens and turkeys begins with the comb and barbs if there is a head on the carcass. Pay attention to the edges of the abdominal incision and to the fat. In geese and ducks, in addition, the heart, liver, and spleen are examined more closely. Carcasses delivered for VSE should be fresh, well bled and plucked (no feathers, fluff, hemp, hairy feathers), no bruising, no trauma, the mouth cavity is cleaned of food and blood residues, the limbs - from dirt, muds, lime build-ups. As well as good body condition that meets the following requirements:

In the carcasses of adult chickens, the muscles are developed satisfactorily; the keel of the sternum is slightly prominent, but not sharply; deposits of subcutaneous fat are insignificant, but may be absent;

The skin of healthy poultry carcasses is white or yellowish with a pink tint, without blue spots. Red skin color and full blood vessels, sometimes visible through the skin, especially under the wings, on the chest and in the groins, indicate poor exsanguination. At the same time, blood or bloody fluid usually flows out at the site of the infection.

Examination of internal organs begins with the intestines and mesentery. Determine the presence of hemorrhages, inflammation, fibrin, helminths, nodules, ulcers and other pathogenic changes characteristic of such infectious diseases as plague, cholera, tuberculosis, myxomatosis, leukemia, etc.

When examining the liver and spleen, their size, consistency, color, the presence of nodules, foci of necrosis, hemorrhages, and the nature of the cut are determined. The mucous membranes are normal, there is no foreign smell.

In the presence of exhaustion, icteric staining of tissues, signs of foreign odor, with damage to the skin, mucous membranes and bones, the carcass is not allowed for sale.

The data of all VSE results of poultry carcasses, as well as internal organs, are entered into a special journal No. 23. When establishing the good quality of poultry carcasses, they are recognized as fit for human consumption and, for the right to sell them on the market, the veterinary expert who conducted the veterinary sanitary examination issues a permit indicating the type of products sold.

9.WSE of fruits and vegetables

The study enrolled fruit - apples, pears, peaches. Fruits are ripe, clean, homogeneous, with their characteristic color, not crumpled, not overripe, without mechanical damage and damage from diseases and pests, contamination, foreign smell and taste, packed in clean, dry and serviceable baskets, sieves, boxes, barrels, buckets and covered clean cloth, parchment, and other materials.

Sanitary assessment. The following are not allowed for sale on the markets:

a) unripe or overripe fruits and berries, wrinkled, contaminated, moldy, with the presence of rot, pests, with an unusual (foreign) smell and taste for them;

b) dried and dried fruits and berries are contaminated, decayed, moldy, affected by pests, with an off-odor, taste and impurities;

c) dry fruits clogged with sand, cuttings, fallen stalks, affected by pests and molds.

Control over the content of nitrates and residues of pesticides in plant foods.

In connection with the use in plant growing of a large number of a wide variety of pesticides and nitrogen-containing mineral fertilizers, a mandatory check of all plant food products for residual quantities of these chemicals with the issuance of toxicological certificates (collective farms) or certificates (individuals). The Regulation on Toxicological Certificates for Food Crop Products (1988) states that, as a control procedure, veterinary and sanitary examination laboratories are given the right to take samples of plant food products from persons selling on the market to determine nitrates and pesticide residues in them. The results of measurements on the EKOTEST-2000 device are expressed in mg of nitrates per kg of the analyzed sample. If the current regulatory and technical documentation requires expressing the result in mg / kg nitrogen nitrates, then the measured value should be multiplied by a factor of 0.2258. MPC values ​​are given in Table 2. Permissible levels of nitrates in plant foods. (San PiN 42-123-4619-88 dated May 30, 1988)

The study included vegetables, potatoes and cabbage. Vegetable products are checked mainly by the organoleptic method in specially designated halls; determine the quality of sorting, appearance, size, maturity, shape, contamination, freshness, smell, color, consistency, the presence of mechanical damage, signs of spoilage, fungal and putrefactive damage by pests, and, if necessary, taste. An important indicator of the suitability of vegetables and fruits for food is the absence of nitrates and radionuclides in them. Plant products containing nitrates and radionuclide substances, like injured ones, quickly lose their turgor and resistance against putrefactive microbes. Therefore, if you suspect falsification or the presence of various harmful substances, additional laboratory tests are carried out. The mandatory requirements for plant products include ensuring their safety for human health. When establishing the good quality of the product and compliance with the consumer property, a label is glued or issued to the owner with permission to sell the goods, indicating the name and quantity of the product, the name of the owner, the examination number, date, the name of the laboratory with the signature of the veterinary specialist who conducted the examination.

The result of the sanitary assessment of plant products is registered in a special journal of form No. 25-vet. The owner's surname, address, quantity of the product, its quality, weight, date and examination number are recorded.

Determination of nitrates.

1) Express - method: a large number of products are checked with the "Nitrate - test" device. The device is switched on, it is adjusted for a certain type of plant products - tomatoes, potatoes, onions, cabbage, etc. (results should not exceed acceptable levels). A rod with a sensitive strip is inserted into the product, the juice from it enters the strip, the results are roughly read. In total, 3-4 effective studies are done by this method, the arithmetic mean is calculated and compared with the tabular values.

2) Quantitative (exact method) method: Vegetable products (carrots, potatoes, cucumbers, etc.) are cut lengthwise into 4 pieces. One of them is grated. A measuring cup is placed on an accurate scale, the balance data is set to "00", exactly 10 g of the grated mass is weighed, exactly 50 ml of alum is poured into another measuring cup, after which the alum is poured into the crushed mass. Timed 2 minutes (for convenience, turn the 2-minute hourglass), and begin to thoroughly mix the contents of the glass with a glass rod. After this time has elapsed, the measuring part of the device (cylindrical stick with a sensitive strip) is lowered into the glass by 1 cm and the result is read in mg / kg. The potato result is 0.85 mg / kg.

10.WSE pork

HSE pigs in mandatory start with heads ... The mandibular lymph nodes, external and internal masseters are cut and examined, making one incision, first on the left and then on the right sides (for cysticercosis). Samples are taken from each masseter, each 40-60 g, for research on trichinosis. Parotid, retropharyngeal lateral and medial lymph nodes are opened. They examine and probe the tongue. To diagnose the chronic (anginal) course of anthrax, special attention, in addition to the mandibular lymph nodes, is paid to the examination of the mucous membrane of the larynx and pharynx, the supraglottic cartilage and tonsils. with the development of the anthrax process, a gelatinous-yellowish edema can be found in the pharynx region, and a gray or almost black plaque on the mucous membrane of the pharynx and larynx. Immediately check the fat for the presence of specific odors. Fat is cut from the submandibular space, grabbing it to its full thickness, with a long strip 1.5-2 cm wide, heated over the flame of a candle until the external fat is strongly melted, after which it is carefully examined for the presence of specific odors (characteristic of working boars, as well as when using in the diet of feed of river or marine origin). In the presence of specific odors in the bacon, meat from the carcass is subjected to a boiling test. To do this, put 8-10 pieces of chopped meat taken from different places from a suspicious carcass in a conical flask of 500 ml, 3-5 g each without visible fat, pour 150-200 ml of distilled water, mix thoroughly and cover with glass or a paper filter, heated in a water bath to 80 - 85 ° C until vapors appear. After that, the glass (paper filter) is lifted from the flask, without removing it from the water bath, and the smell of vapors from the flask, as well as the transparency of the broth and the state of fat on its surface, are assessed. If the broth from the meat is transparent and has a pleasant aroma without foreign odors, and on its surface there are large accumulations of fat, then such meat is fresh, it is released for sale without restrictions, but in this case only after it has been removed from the carcass during varietal cutting of bacon and internal fat, the sale of which on the market is prohibited.

Spleen inspected from the outside, like all other animals, determine the size (according to the type and age of the animal), color, elasticity, the state of the edges. In pigs, the spleen is normally quite flat, with sharp edges, light purple in color, and moderately elastic. Then a longitudinal incision is made and the appearance, color, consistency of the splenic pulp are assessed (the pulp is scraped with the back of the knife). Normally, on the cut, the scraping is moderate or insignificant, it is held tightly on the knife, the edges of the cut are completely aligned (when combined, they completely coincide).

On examination lungs with the trachea (in natural connection) determine their size, state of the edges, consistency, color, nature of the pulmonary pleura, possible overlap of fibrous films on it, the presence of exudate (with pleurisy). The left and right lungs are probed separately with the hands from the lower lobes to the upper ones. Each lung is incised in places of large bronchi (to detect aspiration), the color and consistency of the parenchyma are established. At the same time, the lung tissue is cut in places of seals and areas with a color change. The bronchial left and supra-arterial, then the right bronchial and borderline lymph nodes are sequentially opened. In pigs, mediastinal medial and caudal lymph nodes are absent. Normally, the lymph nodes of an elastic consistency, yellowish-white, dry on a cut. At the slightest inflammation, the lymph nodes of the corresponding inflamed part of the lung are significantly enlarged, juicy in the cut, and may contain a small amount of blood.

Inspection hearts start from the surface of the pericardium, its appearance. Then the pericardium is completely separated from the heart and sent to a container with rejected organs (see the Appendix section of Fig. 5). Since the carcasses and all the organs belonging to them are preliminary checked at the animal slaughtering points, most of them do not end up on the veterinary expert's table in their entire (natural) form. Thus, the heart has already been cut along the greater curvature and cleared of excess blood so that its cavities are accessible for examination. After examining the epicardium, determining its color, size, consistency, the heart is unfolded and opened along the incision to examine the endocardium. Then 3 longitudinal and 3 - 4 transverse incisions are made deep into the myocardium with a wall thickness (distance between the incisions) of about 0.5 - 0.3 cm on each half of the heart, after which the incisions are opened and the myocardium is checked for the presence of cysticercus. At the same time, the heart is examined for defects, the purity of the valves, the state of the myocardium itself (without hemorrhage and necrosis, which excludes foot and mouth disease, erysipeloid and other diseases). So, for example, when examining the heart of pigs, it is necessary to investigate the state of the atrioventricular valves, since the presence of a verrucous endocardium is a sign of a chronic course of erysipelas.

Inspection liver start from the diaphragmatic side, while separating the remains of the diaphragm. In the presence of portal lymph nodes, they are cut and examined, like all previous ones, for color, size, consistency. Determine the size of the organ, blood volume, color, consistency, state of the serous cover of the liver, palpate each lobe separately for the presence of seals. After that, the liver is examined from the visceral side, several longitudinal blind cuts are made, thus opening large bile ducts, in which very often, especially in the southern regions, mature fascioles and dicroceliums can be found. The consistency, color, state of the bile ducts and their contents are assessed. Pay attention to the presence of echinococcal blisters, abscesses, abscesses, to areas of the liver with discoloration and seals, since tuberculous and brucellosis nodules may be present, as well as proliferation of connective tissue (cirrhosis), various dystrophies of organ tissue and other pathological changes. All altered parts of the internal organs, as well as the organs themselves with significant deviations from the norm, are cleaned. Organs, the cleaning of which exceeds 10% of the total mass of the organ, are rejected, exactly like the pathologically altered organs.

Kidney examine after extracting them from the capsule of the perineal fat. First, they are examined from the outer surface and probed, the size, color, and the presence of pathological changes are determined. If you suspect urolithiasis the kidneys are cut longitudinally from the side of the ureter, examining the state of its mucous membrane, as well as the renal pelvis, including the state of the cortical and medullary layers, paying attention to the severity of the border between them.

After carrying out the VSE of all the internal organs available for veterinary sanitary examination, they begin to examine the carcasses (half carcasses or quarters) ... At the same time, the degree of exsanguination is established, attention is paid to the condition of the subcutaneous tissue, the condition of muscles and joints, fat, and their color, smell, consistency, and the presence of changes. Particular attention is paid to the condition of the incision site and the degree of its soaking with blood is assessed. With a strong soaking of the cut with blood, this place is cleaned. Eliminate the presence of edema, tumors, abscesses, phlegmon, hematomas, as well as dirt and odors. All of the above is removed with a slight seizure of healthy tissue, except for the last. It is, if possible, removed by overexposure in a refrigerator compartment on the market. In other cases, when the carcass (half carcasses or quarters) does not cause suspicion, it is impossible to open the lymph nodes and cut the muscles, as this reduces its (their) presentation and suitability for long-term storage. Be sure to examine the remains of the muscles of the legs of the diaphragm on the carcass, cervical muscles, in disadvantaged areas for these diseases, they also take the muscles of the tongue for trichinosis and cysticercosis. Carcasses of wild game animals (wild boar, bear, badger, etc.) are also examined for trichinosis. For research, sections are prepared by cutting out small pieces of muscle the size of a grain of millet with small curved scissors. The scissors are held with the concave side to the muscle, and then the cut remains on their convex side, which is convenient for placing it on the compressorium glass. Slices are taken from different places and laid out in the middle of the cells of the lower glass of the compressor. At least 24 sections are prepared from each investigated carcass, covered with another glass of the compressorium and the sections are crushed between the glasses. Each slice is viewed under a trichinelloscope at a magnification of 50 - 70 times.

The data of all the results of the VSE of carcasses (half carcasses or quarters), as well as internal organs, are entered into a special journal No. 23. In case of a negative result of trichinelloscopy on the carcass and internal organs, the veterinary expert issues a permit for the right to sell on the market.

11.WSE of butter

In the conditions of meat and dairy and food control stations in the markets, during the examination, butter (unsalted, salted) and ghee are distinguished. Butter must contain at least 78% fat, moisture - no more than 20%, salt - no more than 1.5%. Melted butter must contain at least 98% fat and up to 1% moisture. The average oil sample is 10 g.

Organoleptic research. The color is determined after solidification of the molten oil poured into a test tube made of colorless glass, and the uniformity of color is determined on the cross-section of the bar.

The consistency is determined at a temperature of 10-12 ° C by pressing on the oil with a finger.

The smell is determined from melted oil in a clean container. Good-quality oil - white or light yellow in color, uniform throughout the mass, the consistency is dense, homogeneous, the surface of the oil in the cut is shiny, dry or with the presence of tiny droplets of moisture, the taste and smell are clean, characteristic of this type of oil, without foreign tastes and odors. Ghee of soft, granular consistency, with a specific characteristic taste and smell, without foreign tastes and odors, in the molten state, transparent and without sediment, color from white to light yellow, uniform throughout the mass.

Major vices. The use of low-quality milk or cream, violation of the conditions of the technological process and improper storage can cause various defects in the butter.

The fodder taste unites a group of vices that have passed into oil from eaten fodder (garlic, onion, wormwood, radish, sour cabbage etc.).

Cowshed odor occurs when milk is retained in the barn as it absorbs barnyard odor.

The same is the nature of the silage taste and smell. Musty, putrid, cheese flavors arise under the influence of proteolytic microflora in violation of the sanitary and hygienic conditions of the oil production process.

Rancid taste is the most common defect resulting from hydrolysis and oxidation of fat under the action of the lipase enzyme with the formation of aldehydes, ketones, keto acids, etc.

Extraneous odor (oil products, fishy, ​​smoky, burnt, etc.) occurs when cream or butter is stored next to substances that have an odor that is easily adsorbed in products. Oil with pronounced defects is unsuitable for food, it is rejected. It is forbidden to sell oils with various impurities (vegetable oil, cheese, cottage cheese, etc.), as well as in the presence of mold in the inner layers. Outside mold can be removed. With long-term storage, the surface of the oil acquires a dark yellow color and the aftertaste of a salted oil, which wears on
the rank of staff. When stripping a changed layer, the oil is considered sound. If necessary, the content of fat, moisture, sodium chloride and the presence of impurities are determined in the oil.

The fat in oil can be determined using a butyrometer and a formula.

Obtaining milk of high sanitary quality is possible only if veterinary sanitary measures are observed on farms, improved milking hygiene, milk quality control and prevention of cow mastitis.
After milking, milk must be filtered and cooled (no higher than + 10 ° С), no later than 2 hours after milking.
It should not contain inhibiting, neutralizing substances (antibiotics, soda, hydrogen peroxide, formalin, etc.).
Milk intended for the production of baby food must meet the requirements of the highest and first grade, but with a somatic cell content of not more than 500 thousand / cm3.
When receiving each batch of milk, the acidity, purity, density, temperature and fat content are determined.
Bacterial contamination, as well as the mass fraction of protein and the content of somatic cells in milk are determined once every 10 days.
The issue of milk quality is associated with the disease of cows with mastitis, since inflammatory processes occurring in the mammary gland change the composition of milk and its physical and biological properties. It lacks antibacterial substances - lysozymes, the amount of vitamins decreases. In milk from cows sick with mastitis, the amount of casein, lactose, SNF content, and titrated acidity decrease.
At the same time, it increases the content of chlorine, sodium, enzymes (catalase, reductase), as well as the number of leukocytes and pathogenic microorganisms (streptococci, staphylococci, salmonella, etc.). Therefore, milk from cows with mastitis is dangerous to human health.
To identify cows suffering from latent forms of mastitis, the following methods are used, based on the determination of changes in milk that occur during animal disease:
1.the use of dimastin and mastidin;
2. method of settling;
3. bromothymol test;
4. determination of the number of somatic cells (GOST 23453-794);
5.with the help of devices OSM-70 (identifier of latent mastitis), PEDM (device for express diagnostics of mastitis).
Test with mastidin and dimastin
These substances are classified as surfactants. The method is based on the ability of these substances to destroy cells (leukocytes) and release a nuclear substance - deoxyribonucleic acid, which gives a jelly-like clot of varying consistency depending on the number of cells.
Test with mastidine
To study milk from a cow, a 2% solution is used, and a 10% solution is used to detect mastitis milk in the collection. For this purpose, 1 ml of milk is milked into the recesses of the milk control plate from each lobe of the udder and 1 ml of mastidin solution is added. The mixture is stirred with a stick for 10-15 s and the reaction is taken into account for the thickness of the jelly and color change. If the mixture has a protein consistency chicken eggs and the color is dark blue, this indicates that the milk is obtained from cows with mastitis. If there are no clots in the mixture, and the color is light purple, this indicates that the milk comes from a healthy cow.
Dimastin test
For the study, a 5% solution of dimastin is used. The sampling technique is the same as with mastidin. Getting red or red in a jelly mixture color pink indicates inflammation of the udder in cows. If there are no clots in the mixture, and the color is yellow-orange, the milk is from a healthy cow.
It should be borne in mind that the number of cells in milk increases not only with inflammation, but also at the beginning and end of lactation, therefore, a sedimentation test and bacteriological examination must be used to confirm the diagnosis.
Sedimentation sample
In a test tube, 15 ml of milk is milked from each share of the udder and defended at a temperature of 4-5 ° C (in a refrigerator). The tubes are examined after 16-24 hours. If a sediment with a height of more than 1 mm appears on their bottom, this indicates that this is milk from a cow with mastitis.
Bromothymol test
Based on the fact that in an alkaline environment, the reagent becomes blue. To do this, 1 mm of milk is poured into the deepening of the milk plate, 2-3 drops of a 0.5% alcohol solution of bromothymol are added and mixed. Milk from cows with mastitis, depending on the severity of the disease, is colored from dark green to dark blue. Milk from a healthy cow is characterized by a yellow-green coloration.
To determine the number of somatic cells in milk, the drug "mastoprim" is used, which is a mixture of sulfinol 74% and sodium hydroxide 26% calculated on dry matter.
1 ml of milk and 1 ml of an aqueous solution of 2.5% mastoprim are introduced into the deepening of the milk control plate. The milk with the reagent is intensively stirred with a stick. The resulting mixture is lifted up with a stick and the results of the analysis are evaluated. If a homogeneous liquid or a weak clot forms, which slightly stretches behind the stick in the form of a thread, then in 1 ml of milk - up to 500 thousand somatic cells.
In the presence of a pronounced clot, with stirring of which the notch is clearly visible and the clot is not ejected from the well, from "500 thousand to 1 million cells. When a dense clot is formed, which is ejected from the plate well with a stick, more than 1 million cells are contained in 1 ml milk.
The use of devices OSM-70, PEDM is based on the determination of the electrical conductivity of milk. Milk obtained from cows with mastitis has an increased electrical conductivity due to an increase in chlorine and sodium ions in it.
Sanitary assessment of milk
Milk from cows with a clinical form of mastitis is boiled and destroyed, with a latent form of mastitis it is boiled and used for animal feed. The clinical form of mastitis is detected during milking by milking the first streams of milk into a special mug. Cows for latent mastitis should be examined once a month.
In farms affected by tuberculosis milk from cows with clinical manifestations is destroyed by first adding creolin, lysol or other disinfectants to it. Milk from animals that respond positively to tuberculin, but do not have clinical signs, is boiled and used inside the farm. You can use milk from these animals for processing into ghee. From cows that react negatively, milk is pasteurized inside the farm at a temperature of 85 ° C for 30 minutes or at a temperature of 90 ° C for 5 minutes.
With brucellosis, milk is not obtained from cows with clinical forms of the disease.
From cows that react positively, milk is neutralized by boiling and used inside the farm. From negatively reacting cows in a dysfunctional economy, milk is pasteurized at a temperature of 70 ° C for 30 minutes or at a temperature of 85-90 ° C for 20 seconds.
For foot and mouth disease, milk is processed into ghee, or rendered harmless by boiling for 5 minutes, or pasteurized at 80 ° C for 30 minutes.
With leukemia, milk from cows with a clinical form is destroyed. From animals suspected of a disease, milk is boiled for 5 minutes or pasteurized at 85 ° C for 10 minutes.
It is not allowed to sell milk if falsification is established.

The markets can receive milk from cow, goat, sheep, mare, camel, buffalo and other animals, as well as butter and fermented milk products (cream, sour cream, kefir, koumiss, feta cheese, cottage cheese, cheese, fermented baked milk, yogurt, varenets, etc.). ).

Food markets may include milk and dairy products from various dairy enterprises or from large livestock or small private farms.

The sale of milk and dairy products is prohibited if the farm or settlement is unfavorable for anthrax, emkar, smallpox, rabies, peripneumonia, rinderpest, tuberculosis, brucellosis, Aujeszky's disease, paratuberculosis, smallpox, malignant catarrhal fever, lisperiospirosis, yi , Q fever and in cases stipulated by instructions for combating other infectious diseases (leukemia, salmonellosis, etc.), as well as milk from cows vaccinated against anthrax and foot and mouth disease for two weeks, patients with mastitis, endometritis, gastroenteritis, necrobacteriosis and udder actinomycosis.

Milk from cows in the first 7-10 days after calving and in the last 7-10 days before launch is not allowed for sale in the markets. When trading milk and dairy products, it is necessary to require strict adherence to the requirements of the "Trade Rules" and "Rules for the veterinary and sanitary examination of milk and dairy products in the markets." The sale of milk and dairy products on the market prior to the veterinary and sanitary examination is not allowed.

Milk entering the market from farms unfavorable for infectious diseases is tinted with coffee, cocoa, tea, food paint, seized and disposed of under the supervision of the veterinary service in the presence of a representative of the farm or owner, about which an act is drawn up in two copies, one of which is issued to the owner, the other remains in the GLVSE market.

It is not allowed for sale on the market falsified milk and dairy products, including those containing neutralizing and preserving substances, as well as those with unusual odors and taste, whipping, which do not meet the requirements for acidity, density, fat content, bacterial contamination, containing antibiotics and other medicinal products. substances.

It is prohibited to sell milk and dairy products with the following falsification: milk - removing fat, adding water, starch, soda and other impurities; sour cream and cream - an admixture of cottage cheese, starch, flour, kefir; butter - an admixture of milk, cottage cheese, lard, cheese, potatoes, vegetable fats; varenets, fermented baked milk, yogurt - skimming, admixture of soda. Milk obtained from cows with an unknown etiology of the disease is not allowed for sale.

It is allowed to sell milk (cow, goat, sheep) on the markets for the purity signs not lower than the second group, for bacterial contamination not lower than the second class, and the mare - the first group for purity and the second class for bacterial contamination.

Persons selling milk and dairy products in the markets must have personal sanitary medical records or certificates of passing medical examinations established for employees of food enterprises and comply with the sanitary rules for trade in these products.

In accordance with the rules of veterinary sanitary examination, when entering the market, the laboratory takes milk samples of at least 250 ml, sour cream and cream - 15 ml, butter - 10 g, cottage cheese and feta cheese - 20 g, varenets, yogurt, fermented baked milk - 50 ml. Make an average sample of several containers or dishes and heat it up to 20 ºС. Selected samples are examined in the laboratory no later than one hour after taking. At the same time, organoleptic indicators, purity, density and acidity must be monitored; the primary milk is examined additionally for fat content. When the milk is resold from this owner, the fat content of 10% of the dishes is checked. If the owner constantly trades in this market, then the acidity, fat content, bacterial contamination are determined on the market once a month and once every 10 days with systematic sale by farmers, joint-stock companies and other organizations.

The veterinary service of the market checks the cleanliness of the containers. Does not allow products to be sold in galvanized dishes and containers not approved by the State Sanitary and Epidemiological Supervision. If additional research is required in the regional veterinary laboratory, the samples of milk and dairy products taken by the veterinarian are packed in glassware, sealed, labeled and sent with a cover letter. The sale of milk on the market is not permitted pending the results of the study.

The utensils with milk that have passed the control must bear the label of the veterinary sanitary examination laboratory, signed by the market veterinarian. The results of the veterinary examination of milk and dairy products are registered in the journal of the form No. 24-vet.

The veterinary examination of milk provides for an assessment of its danger in an infectious relation, the determination of falsifications, organoleptic defects (change in color, consistency, the presence of impurities), acidity, and the content of harmful substances. When examining milk, first determine its naturalness (conditionality) by organoleptic and physicochemical methods. At the same time, attention is paid to the purity and color of the product. Changes in the color, taste, consistency of milk are observed in some diseases of the uterus and feeding feeds containing carotene and carotenoids. An admixture of flakes or clots in milk indicates a disease of the breast and the presence of certain defects in it.

Milk is a biological product, the quality and physical properties of which are rather labile. Even minor changes in the diet environment, conditions of keeping and in the physiological state of animals lead to some changes in
milk, many of which are defined as defects. Factors causing milk defects include: the physiological state of lactating animals, the disease of the animal, non-observance of the conditions of keeping and feeding, the unsatisfactory condition of livestock buildings, poor condition of pastures, the introduction of drugs into the body, violation of the technology of primary milk processing, various falsifications, etc. defects are associated with a change in color, consistency, smell and taste of milk.

Color defects are of bacterial and fodder origin, as well as with the use of certain drugs and active flavoring substances, with injuries of the udder.

Blue and blue coloration occurs when pigmenting microorganisms multiply, eat forest grasses with blue pigment, with mastitis, breast tuberculosis, store milk in galvanized containers, dilute milk with water, etc. Yellow coloration is caused by microorganisms that produce yellow pigment, but it is also possible when streptococcal mastitis, tuberculosis of the udder, in cases of admixture of colostrum, medicines, etc. Pinkish-red (bloody) coloration is observed in violation of the rules of machine milking, feeding buttercups, euphorbia plants and horsetails, with pyroplasmidosis, udder injuries, etc. Beetroot color of milk is possible. reproduction of fluorescent microorganisms.

Consistency defects occur when animals are sick with foot and mouth disease, intensive reproduction of microorganisms in milk and when feeding some feed. Mucous (viscous) milk is most often caused by mucus-forming cells of lactic acid and putrefactive bacteria, as well as an admixture of colostrum. Fermenting (foaming) milk is possible when bacteria of the Escherichia coli group, yeast, butyric acid microorganisms multiply. Watery milk occurs with tuberculosis, catarrhal mastitis, with an excess of vinasse, beets in the diet, during estrus, when milk is diluted with water, thawing incorrectly frozen milk.

Changes in the technological properties of milk are determined by the physiological state of the body of lactating animals, the use of poor-quality feed, microbiological factors, the presence of antibiotics, soda and other inhibiting substances in milk.

Rapid souring of milk is noted at the end of the dry period, when the animal overheats in the pasture, feeding marsh grass, sour and putrid food, with intensive reproduction in milk of lactic acid bacteria, Escherichia coli bacteria, coccal forms, with disorders of the functions of the digestive system and the mammary gland. Lack of sour milk is noted when feeding field mint, treating cows with antibiotics, in the presence of inhibitory substances, and the development of proteolytic bacteria in milk. Rennet coagulation of milk without souring usually occurs shortly after milking, especially when heated. This is possible when feeding grass from swampy pastures, the development of microorganisms that form rennet, as well as with streptococcal mastitis.

Odor defects are recorded in violation of the sanitary and hygienic conditions for obtaining milk and its improper storage, which contributes to the adsorption of extraneous odors (manure, gasoline, smoke, tar) and the development of microorganisms in it. Ammonia the odor is formed when E. coli bacteria develop in milk or if it is stored in an open container in the barnyard. Cabbage−with an excess of cabbage, green oats, buttercups in the diet. The smell of smoke appears after roasting milk dishes in a smoke oven and pasteurizing milk in smoking ovens. Drug the smell of milk gets from creolin, phenol, tar, iodoform and other drugs. Butyric acid−with oil-acid fermentation; yeast and alcohol, as a result of storing contaminated milk at low temperatures. Putrefactive- as a result of intensive reproduction of putrefactive microorganisms. Musty- when anaerobic microorganisms multiply in tightly closed uncooled milk. Stern−after feeding with frozen cabbage, colza, rapeseed, mustard, rutabaga, vetch, lupine, bard, moldy hay, horsetail, sorrel, shepherd's purse, radish, milkweed, wormwood, mint, marigold. The addition of active substances - hexol, propylamine, acetoacetic acid, betaine and others also changes the organoleptic characteristics of milk. Fishy smell appears when storing milk with fish, feeding animals with fish meal, drinking water with algae.

Defects of taste are of fodder, bacterial and physicochemical origin in violation of the sanitary rules for storing milk.

Bitter taste detected in milk when eating Poland, onions, field mustard, moldy hay, haylage, straw, rotten beets and potatoes; with the development of putrefactive microorganisms and yeast in milk; and also in the milk of old cows. Rancid- from exposure to direct sunlight, at a high storage temperature, during milking in unfinished dishes, as well as under the action of bacteria that cause butyric fermentation and when feeding silage and onions. Salty smack is noted in the milk of old cows, in cases of admixture of colostrum, with mastitis and tuberculosis of the mammary gland. Soapy- when storing freshly milked milk in closed jars, grazing in meadows with horsetail; neutralizing milk with soda; with tuberculosis of the mammary gland. Turnip and rare- when feeding cruciferous root crops and tops (turnips, turnips, rutabagas, radishes); when grazing on stubble covered with rape, field mustard and wild radish. Spicy−due to the use of fresh nettles, hops. Metal- when storing milk in poorly tinned and rusty containers; when drinking water with high content iron oxides. Greasy- as a result of direct exposure to ultraviolet rays. Oxidized- as a result of exposure of milk to direct sunlight. Garlic and onion- when animals eat wild onions, garlic in pastures. Grassy−when eating a large amount of alfalfa, sweet clover, turnip; frozen, rotten and moldy food; intensive development of yeast and mold in milk.

To prevent milk defects and preserve its quality on farms and dairy processing enterprises, it is necessary to exclude all factors that negatively affect the organoleptic characteristics of dairy products.

Defects caused by the absorption of odoriferous vapors can be prevented by observing following rules... Feed, primarily silage, is not stored in premises where livestock is located, since odoriferous substances penetrate through the respiratory system into the blood and milk. All feedstuffs with which active flavoring and aromatic substances can get into milk should be given after milking and in small quantities. Frozen, moldy and odor-contaminated feed should not be given. Do not use detergents and disinfectants that are not approved by the State Veterinary Service and Rosprodnadzor.

Defects caused by changes in milk ingredients do not appear, unless a strong mechanical effect on fresh milk and exposure to factors that contribute to the induction of rancidity. Milk must not be contaminated with heavy metal salts, copper and iron salts, which act as catalysts for chemical processes. It is necessary to eliminate the direct influence of short-wave light, select packaging materials and containers, transport milk without prolonged sharp shaking, observe temperature and time technological processing raw milk, apply technological methods that promote the formation of antioxidants from milk components.

Defects caused by microorganisms can be prevented by thorough washing and disinfection of equipment, containers, containers and other milk pipelines that come into contact with fresh milk, compliance with sanitary and hygienic rules and regulations for obtaining milk, using clean water that meets the requirements for drinking.

It is impossible to use harsh-smelling medications for the treatment of lactating cows and to use in the diet plant feed and feeding that affect non-sensory milk parameters. Milk sold on the markets must comply with the requirements of the law.

In milk on the markets, in addition to organoleptic characteristics, density, acidity and purity are necessarily determined. Fat content when sold for the first time, then in a decade or a month, the presence of impurities of various substances on suspicion of falsification.

Organoleptic characteristics of goat milk are close to cow's milk. Its fat content should be at least 4.4%, density - 1.027−1.038, acidity - no more than 15 ° T.

Sheep's milk is white, contains at least 5% fat, density - 1.034−1.038, acidity - up to 24 ° T.

Mare's milk is sweetish, tart with a bluish tint with a fat content of more than 1%, a density of 1.029-1.033, and an acidity of no more than 7 ° T.

In buffalo milk, the fat content is up to 7-8%, the density is 1.028-1.030, the acidity is 17-19 ° T.

Persons selling milk not from cow, but from other animals must clearly indicate the type of milk for the buyer and observe the hygiene rules of trade in these products. It is not allowed to sell mixed milk from different animals.

When controlling sour cream, the type, uniformity, color, smell, taste, consistency, acidity (60-100 ° T), fat content (more than 25%), starch, cottage cheese, flour and other substances are checked. Sour cream should be clean, without foreign smell, thick, homogeneous, glossy, without grains of fat and casein. It is not allowed to sell sour cream with released whey, viscous, slimy, contaminated, with foreign odors and aftertaste, in a moldy container. Sour cream becomes bitter during long-term storage, with a metallic taste - from containers, greasy - from mold and the addition of fats, viscous - from bacteria, swollen - from abnormal temperatures.

The cream has a uniform consistency, without lumps of fat and casein flakes, without foreign tastes and odors, white or yellowish. They are additionally checked for acidity (17-29 ° T), fat content (18-20%), falsifications (cottage cheese, starch, sour cream).

In cottage cheese, organoleptic indicators are checked for homogeneity (no lumps, non-flowing, non-crumbly), acidity (no higher than 240 ° T), falsification (soda, etc.). Cottage cheese is allowed on sale clean, delicate, without foreign tastes and odors, homogeneous, not crumbly and without lumps, white or yellowish.

In butter, organoleptic indicators, fat content (78%) and moisture (up to 20%), impurities of various substances (margarine, lard, vegetable oil, etc.) are controlled. Ghee has a fat content of 98% and a moisture content of up to 1%. Salted oil contains 78% fat, moisture - up to 20%, salt - no more than 1.5%.

Butter can be without fillers and with fillers, unsalted and salted, sweet cream (without bacteria) and sour cream (with lactic acid bacteria). Vologda butter is made from fresh cream. Homemade butter is made from fresh and sour cream, it can be sweet and sour cream, unsalted and salty. Peasant butter is prepared without washing in buttermilk fat, it can be sweet and sour cream, unsalted and salty. Ghee is prepared by heating to 70-75 ° C, salt is added to it up to 1-1.5%, and for granularity it is kept at 12-13 ° C for three days. Sandwich oil is prepared without washing the fat grains and has a high content of SNF.

With fillers, butter is sold in the form of "Chocolate" (sugar - 18%, cocoa - 25%, fat - 62%, moisture - 16%), "Fruit" (juices - 12%, sugar - 18%, fat - 52% , moisture - 18%), "Honey" (25% honey, 18% moisture, 52% fat), prepare butter with protein, and more.

Butter substitutes are mixtures of milk fat with margarine, vegetable oils, flavorings, stabilizers, which, according to the law, should not be called butter. Thus, Slavyanskoye (unsalted or salted) vegetable oil contains 39%, Gorodskoy - 22-29%, Uglichsky - 32-36%, Dalnevostochny - 12%, Dessertnoy - 24%, "Children's" - 10%. Milk fat in them contains from 60-72% to 79-89%, and in "Children's", "Sandwich" and "Cheese" - no more than 31-55%.

It is not allowed to sell butter that is rancid, moldy, musty, with a cheese and fishy smell, bitter, greasy, loose, crumbly, mealy, with signs of falsification and in a dirty, mint, unmarked container.

In other fermented milk products (fermented milk, varenets, koumiss, yogurt, cheeses, feta cheese), organoleptic indicators, fat content, acidity and, if necessary, impurities of falsification factors are also monitored. The acidity of fermented baked milk is 85-150 ° T and fat content - at least 3.2%, varenets - acidity 75-120 ° T and fat content - 3.2%, yogurt - respectively 80-150 ºT and at least 6%, yogurt - 85 -150 ° T and 3.2%, kefir - 90-120 ° T and not less than 3.2%, kumis - from 60 to 120 ° T and 1.0% and alcohol - 1-3%, feta cheese - 52 ° T and 40%, cheese - 40-50 ° T and 52%, salt - 7%.

In recent years, a large number of cheeses of various names have been marketed.

The bulk of cheeses are produced on the basis of rennet coagulation of milk. The consumer properties of cheeses depend on the quality of the milk used, the technological process, compliance with its parameters, protective treatment of the cheese surface, compliance with sanitary standards and other factors.

Cheese is controlled in appearance, consistency, taste, aroma, color, state of the mass on the cut. The head of cheese is tapped from all sides and the sound is judged. Inspection is subject to up to 1% of the cheese heads received for sale, or all the cheese heads, if there are several of them in the batch. Cheese indicators must meet the standards for the first, second grades and classes A, B, C, C. Class D cheeses are sent for melting, class H are rejected for animal feed.

In total, there are 75 defects in cheeses, of which 29 are appearance, 10 defects of mass, color, appearance, aroma and 25 defects of consistency.

The main requirement for cheeses and feta cheese is production from whole milk obtained from healthy cows, ewes, buffaloes, goats from farms free from infectious animal diseases. Cheese and feta cheese are checked organoleptically and, if necessary, for fat content, moisture and salt content.

In a number of regions of the country, kumis is supplied to the markets. This product is made from the milk of healthy mares in compliance with technological norms and rules. Kumis ripened for 5-6 hours is considered weak (acidity 60-80 ° T), up to a day - medium (80-100 ° T), ripened up to 2 days - strong (101-120 ºT). The alcohol content in weak koumiss is 1%, on average - 1.5% , strong - 3%. The fat content of kumis is at least 1%. Kumis is tested organoleptically for fat and acidity. Kumis, like other fermented milk products that do not meet the requirements of regulatory documents (Federal Law, State Standards, TU, Rules), are not allowed for sale.

Everything lactic acid products are perishable and they are stored at a temperature not exceeding 10 ° С.

Nowadays, milk powder of domestic and foreign producers is more and more often sold on the markets.

Powdered milk allowed for sale on the markets in sealed factory-made packaging. In this case, the packaging must not be damaged.

In the laboratories of veterinary sanitary examination of markets, special attention is paid to identifying various falsifications. For this purpose, approved methods for the study of milk and fermented milk products are used.

The addition of water to milk is determined by the density or dry matter content (below 8%); soda impurity - by mixing 3 ... 5 ml of the product with 0.2% alcoholic solution of rosolic acid (pink-red color) or with bromothymol-blau (dark green color); starch admixture - by adding 2-3 drops of lugol solution to the product (blue color).

Milk and dairy products that do not meet the requirements of the current regulatory documents are not allowed on sale. They are tinted food paints and returned to the owner. Milk and dairy products recognized as dangerous for human consumption are disposed of or destroyed, about which an act is drawn up in the presence of the owner.

Trade in milk and dairy products is allowed in special dairy rows, the tables of which are covered with waterproof material. Only the separate sale of milk from cows, goats, mares, camels, buffaloes, as well as dairy products from the milk of these animals is allowed. Regular traders of dairy products undergo a quarterly medical check-up, observe the rules of personal hygiene and wear aprons and oversleeves.

Milk, cream, butter, cottage cheese, sour cream and other fermented milk products are allowed to be sold from clean (glass, clay, wood, enamel, aluminum) dishes. Milk containers must be tightly closed. Dispensing milk and dairy products should be carried out with clean measuring utensils in compliance with the rules of personal hygiene. It is not allowed to sell milk and fermented milk products in the seller's dishes, including in plastic bottles.

Organoleptic and physicochemical methods of milk research. They include an assessment of color, odor, consistency and taste.

The color of milk is determined in a cylinder of colorless glass under reflected light, the consistency is determined by slowly pouring milk in a thin stream along the wall of the cylinder. The smell is checked at room temperature at the time of opening the vessel or when pouring milk heated to 40-50 ° C. The taste of milk is determined after boiling, while it is not recommended to swallow milk, they only need to moisten the tongue.

When selling milk for the first time or every 10 days (from large farms) or once a month (private farms), the following laboratory tests of milk and dairy products are carried out.

Determination of milk purity. Mechanical contamination (purity) of milk is detected using devices with a filter plate diameter of 27-30 mm, cotton filters or flannel. Take 250 ml of well-mixed milk with a measuring cup and pour it into a container. To accelerate filtration, milk is heated to 30 ° C. Depending on the amount of particles remaining on the filter, milk is divided into 3 groups according to the standard.

♦ the first group - there are no mechanical parts on the filter -

♦ the second group - single particles on the filter;

♦ the third group - a sediment of small and large particles is noticeable (during

moose, particles of hay, sand, etc.).

After the milk is filtered, the filters are placed on a sheet of paper and dried in air.

According to the purity of milk, the observance of the rules of hygiene of milking of cows and the condition of milk containers are assessed.

Determination of milk density. The density of milk is determined using hydrometers of the AMT type (with a thermometer) and AM (without a thermometer). The hydrometer is immersed in milk, carefully poured into the cylinder, so that it does not touch the wall. The numbers on the hydrometer scale increase from top to bottom, as the device sinks deeper with decreasing density. The readings are taken into account no earlier than 1 min after the hydrometer is set in a stationary position, while the eye should be at the level of the milk surface. Readings are recorded along the upper edge of the meniscus with an accuracy of 0.0005. It is recommended to determine the density of milk at a temperature of 20 ° C. If the milk has a different temperature, then the counting results are reduced to 20 ° C using a coefficient, while adding (below 20 ° C) or subtracting (above
20 ° C) 0.2 per degree or calculated according to a special table with the calculation of corrections when controlling milk with a temperature of
15 ° C to 25 ° C.

The density of skim milk is determined with a special hydrometer using a similar method.

The average density of cow's milk ranges from 1.027 ... 1.033 and depends primarily on the breed of the cow. When water is added, the density of the milk decreases.

The accuracy of determining the density of milk is influenced by the presence of mechanical impurities, analysis earlier than two hours after milking, excessively low or high temperature of the test milk, poor mixing or strong agitation, high acidity, soiling of the hydrometer, touching the cylinder wall with the device.

Determination of acidity. The acidity of milk is determined to establish its freshness by a titrimetric method.

In a conical flask with a capacity of 150-200 ml, add 10 ml of milk with a pipette, add 20 ml of freshly boiled water, 3 drops of a 1% alcohol solution of phenolphthalein. The mixture is thoroughly mixed and titrated from a burette with 0.1 N HCl. sodium hydroxide (potassium) solution until a light pink color appears (corresponding to the control standard), which does not disappear within 1 min. A control color standard is prepared immediately prior to analysis. For this purpose, 10 ml of milk is mixed in a conical flask with a capacity of 150-200 ml,
20 ml of boiled distilled water and 1 ml of 2.5% solution of cobalt sulfate. The standard is valid for
1 shift. For analysis in the following days, one drop of formalin must be added to it. The acidity of milk in Turner's degrees is equal to the number of milliliters of 0.1 N. solution of sodium hydroxide (potassium), consumed for neutralization of 10 ml of milk, multiplied by 10. The discrepancy between repeated tests should not exceed 1 ° T.

If necessary, the acidity of milk can be determined without adding water. The resulting acidity result is reduced by 2 ° T.

For mass analysis of milk acidity, the method of limiting acidity is used. It makes sorting milk easier. This method is used in dairies, farms and in laboratories for veterinary sanitary examination of markets. For this purpose, 10 ml of sodium hydroxide (potassium) solution prepared to determine the corresponding degree of acidity is poured into a number of test tubes, then 5 ml of test milk is poured into each test tube and mixed by inversion. If the mixture becomes discolored, then the acidity of this sample is higher than that of the given solution, and if the color is preserved, the acidity of the milk sample is lower than that of the known solution. To prepare a working solution, by which the acidity is determined in Turner degrees, the required amount of 0.1 N is measured into a 1000 ml flask. alkali, add 10 ml of a 1% alcoholic solution of phenolphthalein and fill up to the 1000 ml mark with distilled water. If 80 ml of 0.1 N was added to the flask. sodium hydroxide solution, then the determined acidity is 16 ° Т, 85 ml - 17 ° Т, 90 ml - 18 ° Т, 95 ml - 19 ° Т, 100 ml - 20 ° Т, 105 ml - 21 ° Т, 110 ml - 22 ° T, etc.

The acidity of the cream is determined by the same method, only when a sample of cream is added, the pipette is washed 3-4 times with the mixture and the color control standard for cream is added to 20% fat content
1 ml of a 2.5% solution of cobalt sulfate, for cream with a fat content of more than 20% - add 2 ml of a solution of cobalt sulfate. Calculation of acidity is carried out in the same way as when analyzing milk. For example, 1.8 ml of alkali was used to titrate 10 ml of milk or cream, which means that the acidity of the product is 1.8 ´10 = 18 ° T

The following factors can affect the accuracy of acidity analysis:

♦ inaccurate preparation of a decinormal alkali solution,
1% alcoholic solution of phenolphthalein, 2.5% solution of cobalt sulfate;

♦ use of unboiled distilled water; analysis earlier than 2 hours after milking (since fresh milk contains
a lot of carbon dioxide); the speed of titration (with a fast it will be higher,
than slow);

♦ the temperature of the mixture during titration should be about 20 ° C.
At high temperatures, the results will be lower; when titrating a chilled mixture, the acidity values ​​will be overestimated.

To determine the freshness of milk or cream and the possibility of their pasteurization, a boil test is carried out, since at an acidity of 25 ° T and above, milk curdles during boiling. For this purpose, 10 ml of the product is introduced into a test tube and placed in a boiling water bath for 5 minutes. Flocculation indicates increased acidity. A boil test is determined by the fact of mixing freshly milked milk with already stored milk (morning and evening milk yield), since this milk curdles during boiling. Changes in milk quality depending on acidity are presented in Table 1.

Table 1 - Characteristics of milk depending on acidity

Continuation of table 1

The thermal stability of milk and cream can also be determined by the alcohol test method, based on the denaturation of proteins when mixing milk and ethyl alcohol in equal volumes (2 ml each). For mixing with milk, 68-, 70-, 72-, 75- and 80% solutions of ethyl alcohol are prepared. If no flakes appeared at the bottom of the Petri dish with the test milk or cream, then the milk withstood the alcohol test.

Sometimes in laboratories, pH meters are used to determine the acidity of milk. So, with the help of devices pH-222, pH-232 and others, it is possible to determine the acidity of milk by conventional methods, using the data presented in table 2.

Table 2 - Relationship between pH and titratable acidity

The error in determining acidity using a pH meter is 0.027, and by titration - up to 0.063.

Determination of fat content. The method is based on the ability of sulfuric acid to dissolve milk proteins and protein shells of fat globules, as a result of which fat is released in its pure form and accumulates in the upper layer.

In order to reduce the surface tension of fat globules, isoamyl alcohol is added to milk, which, combining with an acid, forms an amylosulfur ester, which promotes better fat release from the balls and collecting it during centrifugation in the upper part of the butyrometer.

Pour 10 ml of sulfuric acid with a density of 1.81-1.82 g / cm3 (20 ° C) into a clean butyrometer with a pipette. Carefully pipette 0.77 ml of milk. In this case, the tip of the pipette is applied to the wall of the butyrometer at an angle. The milk level in the pipette is set along the lower meniscus line. Milk is poured out of the pipette slowly (it is not allowed to blow milk from the pipette into the butyrometer). Then add 1 ml of isoamyl alcohol with a density of 0.810 to 0.812 g / cm 2 (20 ° C). You can use isoamyl industrial alcohol grade A. Butyrometers are tightly closed with rubber stoppers, shaken until the proteins are completely dissolved, turning 4-5 times until mixing is complete, put in a water bath with stoppers down for 5 minutes at a temperature
65 ° C.

After 5 minutes, the butyrometers are removed from the bath, inserted into the cartridges (glasses) of the centrifuge with the working part to the center, placing them symmetrically (with an unpaired amount, the butyrometer is additionally inserted
with water), close the lid and centrifuge at a speed
1000 rpm for 5 minutes. After that, the butyrometers are removed and the column is adjusted by moving the rubber stopper so that it is in the tube with the scale. The butyrometers are re-placed with their stoppers down in a water bath at (65 ± 2) ° С for 5 min so that the water level is higher than the fat level in the butyrometer. After 5 minutes, they are taken out and the fat is quickly recorded. In this case, the butyrometers must be kept strictly vertical so that the border of the fat layer is at eye level. By moving the plug up and down, set the lower limit of the column of fat on the whole scale of the butyrometer, from it and count the number of divisions to the lower point of the meniscus of the column of fat. The border of separation between the fat column and the mixture should be sharply expressed, and the fat column should be transparent. If there are impurities in the fat column or in the dark yellow ring, the analysis is repeated. The fat volume in 10 small divisions of the butyrometer corresponds to 1% fat in milk.

Fat counting is carried out with an accuracy of one small division of the butyrometer scale. When using a heated centrifuge, the butyrometers are also kept in a water bath before and after centrifugation. When analyzing reconstituted homogenized milk, centrifugation is carried out three times for 5 minutes or once for
15 min, butyrometers are also heated in a water bath.

In parallel (in two butyrometers) analyzes of one sample p

Laboratory stages of sanitary examination of milk: determination of organoleptic properties, physicochemical and bacteriological research.

Milk quality assessment criteria:

compliance with the milk quality standard;

freshness of milk;

falsification of milk (primary and secondary);

the presence of foreign impurities of biogenic and anthropogenic nature.

The most common ways falsifications milk is diluted with water, skimmed and reduced acidity of stale milk. Signs of milk dilution with water are a liquid consistency, a bluish tint, a decrease in specific gravity, fat content and milk solids, as well as the presence of nitrates in milk. Possible secondary falsification milk in order to conceal the dilution with water - the addition of an aqueous solution of starch, which normalizes the consistency and specific gravity of milk, but does not compensate for food and biological value and does not exclude harmful effects impurities contained in the water. Signs of skim milk can be a bluish tint, an increase in specific gravity against the background of a significant decrease in the fat content of milk. Signs of an artificial decrease in milk acidity - normal (16-22 0 T) or abnormally low (less than 16 0 T) acidity, the presence of soda.

1. Organoleptic examination of milk

Appearance and the color of the milk is assessed when viewed in a transparent cylinder (milk volume 50-60 ml). Homogeneity, the presence of sediment and impurities are noted. Natural whole milk should be white Colour with a yellowish tinge. Skim milk or milk diluted with water can have a blue tint. The pink hue can be determined by an admixture of blood, colored bacteria, or depend on the animal's food (beets, carrots, rhubarb).

Consistency milk is determined by the trace remaining on the walls of a transparent vessel after shaking. At normal consistency, a white trace should remain. If the milk is diluted with water, no trace remains. If the milk has a viscous consistency (in the case of multiplication of mucous bacteria in the milk or the presence of starch), then the trace is slimy and viscous.

Smell determined after shaking the milk in a conical flask closed with a watch glass. Natural fresh milk has a pleasant milky smell; a sour smell indicates sour milk; the smell of ammonia or hydrogen sulfide - about the development of putrefactive bacteria. Other odors (oil, kerosene, fish, perfume) may appear in milk if the storage rules are violated.

Taste milk is determined by rinsing the mouth with a small amount of milk (5-10 ml). The taste of high-quality whole milk is pleasant, sweetish. A salty, bitter, astringent taste may indicate an animal's illness. The composition of a lactating animal's feed (for example, an admixture of wormwood) can also change the taste of the milk.

2. Physicochemical research of milk

1). Reductase test . A positive test for reductase is an indirect method for detecting microbial contamination. The test for reductase is carried out using an aqueous solution of the redox indicator methylene blue (the color of the oxidized form is blue, the reduced form is colorless) at a temperature of 37єС (in a thermostat). The methylene blue stock solution is blue. In the presence of reductase in milk, discoloration occurs.

In a sterile test tube (flask), place 20 ml of the test milk and 2-3 drops of a 1% aqueous solution of methylene blue, mix thoroughly, lay on top of the mixture 0.5 ml of sterile vaseline oil and place in a thermostat. The rate of discoloration of methylene blue indicates the degree of microbial contamination of milk (Table 16). On this basis, the quality of milk is assessed with an indication of the quality class.

Table 16. Sanitary assessment of the degree of microbial contamination of milk depending on the time of bleaching with methylene blue reductase

2). Determination of the specific gravity of milk using a lactodensimeter ... Milk (150 ml) is poured into a large glass cylinder, the lactodensimeter is carefully lowered into it to the 1.030 mark on the lower scale so that it does not touch the walls and bottom of the cylinder, and left for 5 minutes. According to the indications on the lower scale, the specific gravity is measured, on the upper scale - the temperature. Specific gravity milk (d) can be expressed in absolute units (g / cm 2) or conventional units (Keven degrees). Each degree of Keven is equal to one thousandth of a g / cm 2, for example, d = 1.027 g / cm 3 = 27K.

Since the specific gravity of milk depends on temperature, for an adequate comparison with the norm (at 20С), the scale readings should be "brought" to 20С. At T> 20С, a correction equal to 0.2Keven for each degree of temperature difference should be added to the value set by the lactodensimeter; at N<20С - следует вычесть эту поправку.

Example. Milk has a specific gravity d 10 = 1.028 g / cm 2, temperature t = + 10С. Then the density of milk, expressed in Keven degrees and "reduced" to 20C, is: d 20 = 28 - (0.2 x 10) = 26 K, which is lower than the normal specific gravity whole milk (1.028-1.034 g / cm 2 =28-34  Keven) by 2Kevena.

3a). Determination of fat content of milk Gerber way ... The essence of the method consists in separating the fat phase from milk using sulfuric acid and isoamyl alcohol and measuring the fat volume in a Gerber 14 butyrometer after centrifugation in a milk centrifuge for 5 minutes. During centrifugation of a mixture of milk, sulfuric acid and isoamyl alcohol, phase separation occurs, the fat is collected in the narrowed upper end of the vessel, along the length of which divisions from 0 to 6 are plotted, each division corresponds to 1% fat (measurement accuracy 0.1%).

3b) Determination of fat content of milk by acid-free method . 5 ml of 10% soda solution, 10 ml of test milk, 3-3.5 ml of alcohol mixture (amyl alcohol: ethanol = 1: 6) and 2-5 drops of phenolphthalein working solution are poured into the Gerber butyrometer. The butyrometer is closed with a stopper, shaken until a homogeneous liquid is formed, placed with the stopper down in a water bath (65-70С) for 5 minutes, and then centrifuged in a milk centrifuge. After stopping it, the butyrometer is carefully transferred to a water bath and kept there for 3-4 minutes, after which the fat content is determined on a scale. The noted result is compared with the norm of fat content of whole milk (fat content not less than 3.2%).

4). Calculation of the dry residue . The dry matter of milk is made up of proteins, fats, carbohydrates and mineral salts. The dry residue can be determined by weight, or you can use the calculation according to the Farington formula: C = [(4.8  F + d 4 20) / 4] + 0.5, where F is the fat content (%); d 4 20 - density (degrees of Keven); 4.8; 4 and 0.5 are empirical coefficients.

5). Determination of milk acidity by titration 15 . The acidity of milk is measured in Turner's degrees (0 T): 1 0 T corresponds to the volume (ml) of 0.1 N sodium hydroxide solution used to neutralize acids in 100 ml of milk. To determine the acidity of milk, 10 ml of milk, 20 ml of distilled water, 3-4 drops of 1% phenolphthalein solution are poured into a conical flask. The mixture is titrated with a 0.1 N alkali solution until a stable slightly pinkish coloration appears. The volume of the alkali solution used for titration is multiplied by 10 (to be converted to 100 ml of milk). The acidity of milk should be estimated based on the fact that the acidity of fresh milk = 16-19 T, fresh enough - 20-22 T, more than 23 T has stale milk.

6). Samples for falsification of milk

6a). Definition soda in milk. Soda can be added to milk to hide its acidity. By neutralizing lactic acid, soda does not delay the development of microorganisms in milk, which increases the epidemic risk, and contributes to the destruction of vitamin C, which reduces the nutritional value of the product. Baking soda milk is classified as adulterated and unfit for human consumption. Rosolic acid serves as an indicator for detecting soda in milk.

5 ml of milk is poured into a test tube and 4-5 drops of 0.2% alcoholic solution of rosolic acid are added. In the presence of soda, milk turns crimson; in the absence of soda, a yellow-brown color appears. The measurement limit is 0.1% soda in milk.

6b). Definition starch in milk. Starch is added to milk for the purpose of falsification to give it a thicker consistency after dilution with water. An indicator for the presence of starch is Lugol's solution (KI, I 2). Milk with starch addition is classified as adulterated and unfit for human consumption.

10-15 ml of the test milk and 1 ml of Lugol's solution are poured into a conical flask. In the presence of starch, the milk turns blue, without starch it turns brown.

6c) Test for nitrates which can appear in milk as a result of dilution of milk with water containing nitrates. 10 ml of milk and 0.3 ml of 20% CaCO 3 solution are poured into the flask. The mixture is boiled until milk coagulates, cooled and filtered. 1-2 crystals of diphenylamine are placed in a porcelain cup and 1 ml of concentrated sulfuric acid is poured. A few drops of filtrate are carefully layered on the edge of the cup. The appearance of a blue color indicates the presence of nitrites and nitrates.

Based on the results of the examination, they give a conclusion about the good quality, freshness and wholeness of the milk. At the same time, they are guided by the norms for whole, fresh and good-quality milk.

Milk and dairy products are valuable animal foods. 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 correct organization of 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 conducting veterinary sanitary examination of milk and dairy products is determined by the current regulatory documents.

Requirements for milk when purchasing

The 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 in farms free from infectious diseases, in accordance with the current veterinary and sanitary rules and the international veterinary code. All purchased milk, depending on its organoleptic and laboratory parameters, is divided into three varieties, 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

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

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

When sending milk, a veterinary certificate form No. 2 is drawn up (certificate form No. 4 for the district), a certificate of quality and safety and a consignment note (for legal entities). Milk is transported by specialized vehicles (in tanks for food liquids, metal flasks or other containers permitted by the sanitary and epidemiological supervision of the Russian Federation) in accordance with the rules for the transportation of perishable goods at temperatures from +2 to + 8 ° С for no longer than 12 hours. If the transportation regimes are violated, milk is classified as non-graded.

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 complex of organoleptic, physicochemical and microbiological studies.

Examination of accompanying documents

When delivering milk to the market by individuals, they must submit a veterinary certificate form No. 2 or a veterinary certificate form No. 4 (for transportation within the district). 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 planned diagnostic tests (for tuberculosis, brucellosis, etc.), vaccinations and studies for latent mastitis. This document is valid for 1 month. In addition, a person selling milk on the market must have a health book of the established form.

If the supplier is an organization, then a veterinary certificate form No. 2 or a veterinary certificate form No. 4 (for transportation within the region) valid for 3 days, a consignment note, and a certificate of quality are issued for each batch of milk, which indicate the results of milk research obtained 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 absorb strong odors. Therefore, the milk container must be hermetically sealed. In addition, the milk tata must be made of food material approved by the Sanitary and Epidemiological Supervision of the Russian Federation and be clean in a sanitary sense.

Most often, for transporting milk I use special milk tankers, milk flasks made of aluminum and stainless steel, enameled dishes without chips, containers made of glass and food grade plastic. In transport, milk must not be transported together with strongly smelling, poisonous 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 testing. Before sampling, the milk is thoroughly mixed, moving it up and down 8-10 times in flasks with a whorl, in road and rail tank cars with mechanical stirrers for 3-4 minutes and 15-20 minutes, respectively. When taking spot milk samples, use 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). When taking samples with a sampler, it must be lowered into the container slowly, with an open top end. The taken samples are placed in a clean container made of a material approved by the RF Sanitary and Epidemiological Inspectorate, with a hermetically sealed lid.

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

Organoleptic examination of milk

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

Determination of appearance, color and consistency is carried out in accordance with GOST R 52054-2003

Milk color determined in daylight in a colorless glass cylinder.

Consistency milk is determined by pouring a milk sample into a colorless glass cylinder. Cow's milk should be a thick, homogeneous liquid without sediment and clots. Milk from cows with mastitis can be slimy and contain clots and flakes. Clots and flakes can form in sour milk, as well as when fatty milk is quickly cooled. In order to find out the reason for the formation of flakes and clots, milk is heated to 30-40˚С. in this case, the fat flakes, in contrast to mastitis, dissolve.

The organoleptic characteristics of milk, depending on its type, 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

Determination of physical and chemical parameters of milk

The following laboratory parameters are determined in each batch of milk: titratable acidity, temperature, mass fraction fat, density or freezing point, purity group and heat resistance group. At least once a decade in the test milk, the following is determined: bacterial contamination, the content of somatic cells and the presence of inhibiting substances, and the protein content is determined 2 times a month. If you suspect that the milk has been cooked, check for alkaline phosphatase in the milk. According to the results of organoleptic and laboratory tests, 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 milk temperature 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, bag. When receiving milk directly on farms, the temperature is measured in transport containers immediately after they are filled. Before measuring the temperature, the milk in the cisterns of the flasks is stirred.

To measure the temperature of milk, glass liquid thermometers in a frame are used in accordance with GOST R 51652-2000. The thermometer is immersed in milk to the lower digitized mark and kept for at least 2 minutes. The 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 to the nearest whole number. And the results of digital thermometers are determined by 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 neutralizing the acids contained in the product with sodium hydroxide solution in the presence of phenolphthalein indicator.

In a flask with a capacity of 100 to 250 cm 3, measure 20 ml of distilled water, 10 ml of the analyzed milk, and three drops of 1% solution of phenolphthalein. 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 slightly pink color appears, for milk and cream, corresponding to the control standard of color, which does not disappear within 1 min.

To prepare a control standard. In a flask with a capacity of 100 or 250 cm 3, measure 10 ml of milk (5 g of dairy products) and 20 ml for milk (30-50 ml for dairy products) distilled water and 1 cm 3 of a 2.5% solution of cobalt sulfate. The mixture is thoroughly mixed. The shelf life of the standard is no more than 8 hours at room temperature.

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

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, 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, remove it with a stirrer. Place the cylinder with the test sample on a flat horizontal surface, measure the temperature of the sample. The temperature readings are counted not earlier than 2-3 minutes after lowering the thermometer into the sample.

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

Table 3

Reducing the density of 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 on the thermometer scale. The first reading of the density readings is carried out visually from the scale of the hydrometer after it has been established in a stationary position. After that, the hydrometer is carefully raised to the level of the ballast in it and again lowered, 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 density readings, the eye should be at the level of the meniscus. The reading is carried out along the upper edge of the meniscus (see Fig. 1).

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

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

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

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

Determination of the group of milk purity (GOST 8218-89)

Determination of the milk purity group is carried out using a device for determining the purity of milk with a filtering 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 warmed up to 35 ° C and pour it into the vessel of the device. At the end of the filtration, remove the filter, place it on a sheet of parchment paper and compare it with the standard. According to purity, milk is divided into 3 groups (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) with a dispenser and carefully so that the liquids do not mix, add 10.77 ml of milk with a pipette, attaching the tip to the wall of the neck butyrometer at an angle (the milk level in the pipette is set at the lower level of the meniscus). Blowing milk out of the 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 butter 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) - creamy

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

If the number of butyrometers is odd, 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 taken out of the centrifuge and the column of fat in the butyrometer is adjusted by moving the rubber stopper so that it is in the tube with a scale. Then the butyrometers are re-immersed, stoppers down, in a water bath at a temperature of 65 ± 2 ° C.

Rice. 3 Automatic pipette for collecting sulfuric acid.

Automatic pipette for the collection of sulfuric acid.

After 5 minutes, the butyrometers are removed from the water bath and the fat is quickly read. For this, the butyrometer is held vertically with the fat border 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 fat column should be transparent.

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

division of 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 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 rapidly 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 predetermined circuit and a galvanometer or digital indicator, a sample stirrer and crystallization inducer, and sample tubes.

Pour out or transfer with a pipette a sample of the test milk in an 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 them with a soft, clean, lint-free cloth).

Insert the 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 devices, the temperature can be observed on a digital scale; in other devices, the required accuracy of calling crystallization is ensured when the galvanometer needle coincides with the corresponding mark).

Determination of milk solids (SOM) and

dry skimmed milk residue (COOM)

SOM% = 4.9 W% + P ° A +0.5

СООМ% = СООМ% -Ж%

where: W% - fat content of milk in%

Р ° А - density in degrees of hydrometer

(for example, the density is 1028 kg / m 3 = 28 ° A).

Normal milk yield is from 11% to 17%, SOM> 8%.

Determination of heat resistance 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 fully or partially denatured when mixing equal volumes of milk or cream with alcohol. Milk for determination of heat resistance by alcohol test is examined at a temperature of (20 + 2) ° С, and the cream is heated in a glass in a water bath to a temperature of up to (43 ± 2) ° С, stirred and cooled to a temperature of (20 ± 2) ° С.

The thermal stability of milk and cream on an alcoholic 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 an alcoholic sample, kg / m3, at (20.0 ± 0.1) ° С should be equal to: for a 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.

2 ml of the test milk or cream is poured into a clean dry Petri dish, 2 ml of ethyl alcohol of the required volume fraction is poured, the mixture is thoroughly stirred in a circular motion. After 2 minutes, observe the change in the consistency of the analyzed milk or cream.

Taking into account the reaction. If no flakes appear at the bottom of the Petri dish during the flowing down of the analyzed mixtures of milk or cream with alcohol, it is considered that they have withstood the alcohol test.

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

Table 5

Heat resistance groups of milk

Determination of the mass fraction of protein and the 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 in one of the following ways:

chemical - by alkalizing the solution, distilling ammonia with water vapor, 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 a mineralized sample.

The mass fraction of 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, 10 cm 3 of sulfuric acid and 10 cm 3 of hydrogen peroxide or 0.5 g of potassium permanganate are added and then heated on an electric stove until the vigorous foaming of the contents stops 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 fraction of total nitrogen is determined by chemical or electrochemical methods with indication of the equivalence point.

Chemical method. The mineralizate in a Kjeldahl flask or a test tube is dissolved in 20 cm 3 of distilled water and attached to the distillation apparatus (see Fig. 4 (1 - plate, 2 - flask with water, 3 - separating funnel, 4 - droplet catcher, 5 - quartz tube 6 - refrigerator 7 - receiving flask)). In a conical flask with a capacity of 250 cm 3, measure with a measuring cylinder 20 cm 3 of a mixture of boric acid solution with an indicator solution and place it under the refrigerator of a boric acid solution with an indicator solution (methylene blue or brilliant green). Measure with a measuring 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 funnel valve is closed immediately. Close the clamp on the steam outlet line and open the clamp on the steam supply line from the steam generator flask to the Kjeldahl flask or test tube. The distillation is carried out until the condensate volume reaches 90 - 120 cm 3 (distillation time - 5-10 minutes).

Table 6

Changing the color of the solution during titration

with various indicators

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

At the same time, a control reaction was performed without milk.

Processing of measurement results

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

X% = 1.4 · (V- V 1) · C

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

V1 - volume of acid consumed for titration during control measurement, cm 3

C - concentration of hydrochloric acid, mol / dm 3

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

1.4 - conversion factor of the volume of acid in the mass fraction of total nitrogen

Protein mass fraction 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 brought to the mark with distilled water and mixed.

0.2 cm 3 of a neutralizing solution is introduced into 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 a mineralizate solution and the button is turned on "Start" automatic titration. The ammonia titration process is carried out automatically. At the end of the process, the device turns off. The digital indicator readings correspond to the mass of the total nitrogen in the sample.

Determination of the mass fraction of moisture in butter.

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

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

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 the direct inoculation method. Serial dilutions are prepared from a milk sample in sterile 0.9% NaCl solution from 1:10 to 1: 1,000,000. Of the last three dilutions, I make 2-3 inoculations (1 ml) in Petri dishes and fill them with melted mesopatamia agar or a special medium. Inoculated dishes are placed in a thermostat at 37 ° C for two days when inoculated 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. By the duration of the color change, the bacterial contamination of raw milk is assessed.

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

In the absence of a reducer, you can use a water bath at a temperature of 37-38 ° C. After immersing the test tube with milk, the water in the reducer or water bath 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 after the start of the analysis. The end of the analysis is considered the moment of discoloration of the milk, 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. Disregard the appearance of milk coloration in these tubes upon shaking.

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 a working solution (0.014%) of resazurin is poured into a sterile test tube, which is prepared from a basic solution (0.05%) and 10 ml of the test milk, closed with a stopper, mixed by slowly turning the test 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

Determination of coli-titer of milk

A coli-titer is the smallest amount of milk that contains one bacterium of the E. coli group.

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

Minimum allowable values coli-titer 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: 100000. Then, inoculation is made from each dilution (1 ml) into a test tube with Kessler's medium (with lactose and gas). To determine the titer of pasteurized milk in 3 tubes with Kessler's medium

Table 9

Determination of the coli-titer of raw milk

Table 10

Determination of the coli-titer of pasteurized milk

make a sowing of 1 ml of milk and make a sowing in 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 tank.

Determination of the coli-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. Into the well of the PMK-1 plate, add 1 ml of thoroughly mixed milk and add 1 ml of an aqueous solution of the Mastoprim preparation. Milk with the drug is intensively mixed with a wooden, plastic or glass rod for 10 s. The resulting mixture from the plate well with continuous vigorous stirring is raised with a stick upwards by 50-70 mm, after which the analysis results are evaluated within no more than 60 seconds.

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

1. A homogeneous liquid or a weak clot that slightly stretches behind the stick in the form of a thread up to 500 thousand.

2. Pronounced clot, with stirring of which the notch at the bottom of the plate well is clearly visible. The clot is not ejected from the hole from 500 thousand to 1 mil.

3. A dense clot, which is ejected by a stick from the plate-hole over 1 mil.

For a more accurate determination of the number of somatic cells, a viscometer is used.

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

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

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

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

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

When carrying out low-temperature pasteurization in milk, alkaline phosphatase is destroyed, and during high-temperature pasteurization, the enzyme peroxidase 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 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 crystals of potassium iodide are dissolved.

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.

Statement of the reaction. In a test tube with 5 ml. 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 poured into milk, the contents of the test tube are mixed with rotary 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: pour 0.5 cm of a 1% solution of starch, 2 drops of a 10% solution of potassium iodide into each test tube with products prepared as indicated above, and 5 drops of 0.5% hydrogen peroxide solution, mix the contents of the 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. Consequently, 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 tubes become dark blue.

The sensitivity of the method allows detecting the addition of at least 5% of unpasteurized dairy products to pasteurized

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. Free phenol released during hydrolysis in the presence of an oxidizing agent gives a pink coloration with 4-aminoantipyrine.

Preparation of solution A. 1.25 g of 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. 25% ammonia solution add 40 g of ammonium chloride, previously dissolved in 100 ml. of distilled water, and brought 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 vials in the refrigerator. Shelf life is not more than 1 month. Yellowed solutions are unsuitable for work.

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

Preparation of a precipitant for 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 test tube are mixed and placed in a water bath heated to 40-45 ° C for 30 minutes. Add 5 cm 3 of a zinc-copper precipitant to a test tube removed from a water bath, thoroughly mix the contents of the test tube and put it back in a water bath with a temperature of 40-45 ° C for 10 minutes. After removing the test tube from the bath, visually compare the contents of the test tube with 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 test tube (solution separated from the precipitated protein) is colorless, i.e., similar to the contents of test tubes of the control experiment. Consequently, milk and dairy products were pasteurized at a temperature not lower than 63 ° C.

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. Phenolphthalein released during hydrolysis in an alkaline medium gives a pink color.

Statement of the reaction. In a test tube, measure 2 ml of milk, 2 ml of distilled water and 1 ml of sodium phenolphthalein phosphate in an ammonia buffer. Then the contents of the test tube are closed with a stopper, shaken and placed in a water bath. The content of the test tube is assessed after 10 minutes and after 1 hour.

In the absence of the phosphatase enzyme in milk and dairy products, the color of the contents of the test tube does not change. Consequently, milk and dairy products were pasteurized at a temperature not lower than 63 ° C. In the presence of phosphatase in milk and dairy products, the contents of the tube acquire a color from light pink to bright pink. Consequently, 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 allows detecting the addition of at least 2% of unpasteurized dairy products to pasteurized ones.

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

Definition of falsification of milk and dairy products

Milk falsification can be natural or artificial. Natural falsification is understood as the deliberate 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 timing of implementation, prevention of milk souring, etc.

Determination of falsification of milk with water.

To increase the volume of milk, it is diluted with water, while the organoleptic and laboratory parameters of milk change. The taste and smell of milk diluted milk is weakened, the consistency of the liquid is 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 a refrigerator at a temperature of (6 ± 2) ° C.

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

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

Into the test tubes with the test milk and the control sample, add 1 cm 3 of the basic solution of resazurin with a temperature of (20 ± 2) ºС. The contents of the tubes are mixed by inverting twice.

The test tubes with the test milk and the 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) ° С 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 tubes will have a pink or white color.

If there are inhibitory substances in the milk, the contents of the 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 in accordance with GOST 9225-84.

Determination of falsification of milk with formalin

1 ml of the test milk is placed in a test tube and 1 ml of Rigel's reagent (a mixture of concentrated sulfuric and nitric acids) is added. If formalin is present in milk, a blue-violet ring is formed at the border of milk and Rigel's reagent.

Determination of falsification of milk with hydrogen peroxide

GOST 24067-80

Place 1 cm 3 of the test milk into a test tube, without stirring, add two drops of a solution of sulfuric acid and 0.2 cm 3 of a 3% solution of potassium iodide starch.

After 10 minutes, observe the color change of the solution in the test tube placed in a rack, not allowing it to be shaken.

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

Definition of milk falsification

chromopic (potassium dichromate)

Place 1 cm 3 of the test milk in a test tube, add 5-7 drops of 5-10% solution of silver nitrate. The contents of the tube are mixed. If there is chromic peak in milk, it becomes lemon-yellow or red-yellow in color.

Determination of falsification of milk with soda.

To prevent sour milk and dairy products, they are falsified with soda.

Soda dissolves poorly 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 to 3-5 ml of the test milk or dairy product and a few drops of a 0.2% alcohol solution of rosolic acid. In the presence of soda, the contents in the test tube turn pink-red, and in the absence, in orange.

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

Determination of falsification of milk by starch

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 test tube are shaken thoroughly. The appearance after 1-2 minutes of a blue color indicates the presence of starch in the test sample.

Definition of falsification of sour cream

yogurt or cottage cheese

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