Food is a breeding ground for microbes. Knowledge of the nature of the microflora of food products and the microbiological processes occurring in them is necessary for catering workers to organize the correct storage, processing of raw materials, preparation of dishes and the sale of finished food.

1) Microbiology of meat and meat products.

The muscles and blood of healthy livestock do not contain microbes. The meat is contaminated with microbes when processed in meat processing plants. In the process of slaughtering cattle, the primary processing of carcasses, microbes from the skin of animals, from the intestines, from the slaughtering and processing tool, reach the surface, and through the lymphatic and blood vessels, they penetrate into the meat carcasses. The dissemination of carcasses increases when they are transported.

The development of microbes is facilitated by the increased temperature and humidity of the surrounding air.

Slows down the action of microbes and their development:

Low temperature of carcasses;

Fatness of the animal;

High amount of fat

The presence of a drying crust on the surface of the carcasses

On 1 cm2 of the surface of meat, up to several hundred thousand microbes are found, mainly such as: putrefactive bacillus, salmonella, E. coli, mold fungi.

To preserve the quality of meat carcasses, pieces of meat, the conditions and terms of its storage should be strictly observed.

Minced meat has a much more abundant microflora than pieces of meat, because the surface of contact of minced meat with air, a meat grinder increases, tissue destruction occurs, partial leakage of meat juice, which creates favorable conditions for the reproduction and development of microbes. Therefore, the minced meat should be stored for a short time and at a low temperature.

Poultry meat poses a greater health hazard than animal meat, because the bird often comes half-gutted: with the head, legs, internal organs, in which many microorganisms are found. In addition, poultry, especially waterfowl (geese, ducks), have a lot of Salmonella in the intestines, which, during processing (removal of the intestines) and pre-slaughter fasting, the birds seed the entire carcass.

Special jobs are organized at catering establishments for processing poultry.

Meat by-products are heavily contaminated with microorganisms, of the same nature as that of meat, as a result of their ingestion from external environment on the external organs during the life of animals (legs, tails, heads, ears) and high moisture content (liver, nights, brains). Therefore, by-products in catering always come frozen and processed in the butcher's shop at separate workplaces.

Sausages are contaminated with microbes both inside and outside. Microbes get inside the loaves with minced sausage, which is seeded during its preparation. During the heat treatment of sausages (steam cooking, smoking with hot smoke), most of these microbes die. Spores of bacilli remain viable, among which botulinus spores are especially dangerous. When storing sausages, it is necessary to comply with the conditions, shelf life.

Least Rack Storage Unit boiled sausages, brawn, jellies, especially those prepared from lower grades of meat or from raw materials heavily seeded with microbes (trimmings, offal). In addition, these products have high humidity.

Semi-smoked, boiled smoked, smoked sausages more stable in storage due to less microbial contamination of high-quality raw materials, lower humidity, high salt content and treatment with smoke substances during smoking.

2) Microbiology of fish and fish products.

Fish is perishable because it is heavily contaminated with microbes outside, inside the intestines and in the gills of the head. After the catch, all these microbes penetrate into the fish tissue, causing its spoilage. Significant contamination of fish tissue by microbes occurs from diseased fish specimens during their cutting, processing and storage.

In fish, micrococci, sarcins, (spherical bacteria) putrefactive sticks are found. Particularly dangerous is the botulinus bacillus, which causes severe poisoning - botulism. To prevent this poisoning, the caught large fish (sturgeon) is immediately gutted and frozen, thus preventing the release of the toxin (poison) of botulinus, which is life-threatening.

Fresh frozen fish has a longer shelf life. microbiological processes are suspended or slower, sometimes causing the development of mold fungi on the surface of fish in the form of single point colonies.

The freshness of the fish is judged by the smell, the color of the gills and the texture of the tissue.

Salted, dried, smoked fish more stable during storage, because the process of its production (salt, dehydration, smoke substances) creates unfavorable conditions for the development of microbes.

Non-fish products of the sea (crustaceans, bivalve molluscs, cephalopods) are seeded with microbes of sea water, silt, from the intestines of the animals themselves, which makes them perishable, easily rotting under the influence of putrefactive microbes. There are cases of foodborne infections (typhoid fever) and food poisoning when people eat raw shellfish (oyster) meat.

3) Microbiology of sterilized canned food.

Hermetically sealed canned food from vegetables, fruits, meat, fish, sterilized in accordance with the established regime (time, temperature), do not contain microbes and are stable during storage.

However, it is known that canned food can cause microbial poisoning and spoilage of the product in them. This is due to the fact that spore bacteria with a higher resistance to the sterilization regime are found in canned food: spores of potato bacillus, butyric acid bacteria and spores of botulinus. Having retained their viability, these microorganisms, as a result of development, emit carbon dioxide, hydrogen, hydrogen sulfide, which swell the can. This phenomenon is called biological bombing.

Bomb cans can be poisonous due to the toxin content of the botulinus stick and must be destroyed.

Some spore anaerobic microbes that survived after insufficient sterilization can spoil the contents of canned food without the formation of gases, without external changes in the can. Such spoilage of canned food is detected when the can is opened and is called flat souring. This is most often observed in canned food with slightly acidic content: green pea, canned meat and sausages, canned baby food.

4) Microbiology of milk and dairy products.

Milk is an excellent medium for the development of microorganisms, which get into it from the udder and hair of animals, from the hands of milkmaids, litter of a barnyard, inventory, etc.

Several hundred thousand microbes are found in 1 ml of milk. When milk is cooled to + 3 ° C, the number of microbes decreases under the action of bactericidal substances of freshly milked milk within 2-40 hours. Then comes the rapid development of all microbes with a predominance of the development of lactic acid bacteria. Milk accumulates lactic acid and antibiotics secreted by these microbes, which leads to the destruction of all microorganisms and lactic acid bacteria. Milk turns sour, favorable conditions are created for the development of mold fungi, and then putrefactive microbes. Putrid spoilage of milk occurs.

In pasteurized milk (heated to 63-90 ° C), almost all lactic acid bacteria and bactericidal substances die, but the spore forms of microbes remain. Additional contamination of milk with putrefactive or pathogenic microbes leads to milk spoilage and makes it hazardous to health. Therefore, pasteurized milk requires a certain storage regime (+ 4 ° C to 36 hours).

Sterilized milk (heated to 140 ° C in a few seconds), prepared from fresh high-quality milk, does not contain microbes and therefore stays in an airtight package for up to 4 months.

Disease-causing microbes - causative agents of dysentery, typhoid fever, tuberculosis - can get into milk. Therefore, in public catering, milk is necessarily boiled.

Milk powder is an unfavorable environment for the development of microbes, although all spores of bacilli, heat-resistant non-spore species of micrococci, streptococci, some lactic acid bacteria, mold fungi are preserved in it. These microbes can cause mold and sourness when milk is highly moistened.

Condensed milk is well preserved, because high sugar concentration and sterilization kill most microbes. Heavily seeded raw materials from which condensed milk is made can lead to fermentation or decay.

Fermented dairy products contain microorganisms that are part of the factory starter culture, yeast - for kefir and kumis. In addition, the microflora of sour milk products depends on the microbes in the milk and the sanitary condition of the equipment.

5) Microbiology of edible fats.

Butter, which contains a lot of water, proteins, carbohydrates, is seeded with hundreds of thousands of putrefactive, lactic acid bacteria, and sour butter also contains aromatic cocci. Fat-splitting bacteria can cause fats to go rancid, imparting a bitter taste to the oil. therefore butter not stored for a long time (up to 10 days) at a temperature of + 4 ° C.

Rendered animal fats and vegetable oils containing little moisture (up to 0.3%), resistant to microbes, and therefore well stored.

6) Microbiology of eggs and egg products.

The egg is contaminated with microorganisms during laying. The inner contents of a healthy bird's egg remain germ-free for a long time, thanks to the natural immune substance of the egg - lysozyme, a dried film on the surface of the egg and the shell membrane, which prevents the penetration of microbes inside. During storage, the protective forces of the egg weaken, the shell and shell shells are destroyed. Microbes (Escherichia coli, Proteus, staphylococcus, mold fungi) penetrate the egg through the pores, exposing it to spoilage: protein decay with the release of an unpleasant odor (ammonia, hydrogen sulfide), mold with the appearance of black spots under the shell.

A sick bird, often a water bird, may contain salmonella in the intestines, which colonize the egg inside when it is formed in the bird's body and on the shell. Such an egg causes a disease in humans - salmonellosis.

Melange (a mixture of protein and yolk) is a perishable egg product, therefore it always goes to public catering in frozen form and is used only in dough, products from which are subjected to prolonged heat treatment. Melange supplied to public catering, according to the standard, should not contain pathogenic microbes and Escherichia coli.

Egg powder contains several hundred thousand microorganisms in 1 g of the product, including E. coli, salmonella, putrefactive bacillus (proteus). Egg powder should be stored dry (moisture up to 8.5%), and when diluted, it should be quickly subjected to thorough heat treatment at a high temperature.

7) Microbiology of vegetables, fruits and products of their processing.

Fresh vegetables, fruits are abundantly seeded with microorganisms that get on them from soil, water and air. Thanks to the peel, organic juice acids, glycosides, essential oils, phytoncides, fresh vegetables and fruits have strong immunity, which is enhanced by the presence of yeast, acetic acid, lactic acid and other bacteria on the surface of vegetables and fruits.

Damage to vegetables and fruits occurs as a result of overripening during long-term storage and violation of the integrity of their cover. Microbes invade the inside of the pulp and cause first mold, and then rotting of the fruit.

On the surface of all vegetables and fruits, there can be pathogenic (disease-causing) bacteria that cause dysentery, typhoid fever, cholera. Therefore, vegetables and fruits eaten raw require thorough washing.

Pickled vegetables, fruits contain lactic acid, acetic acid bacteria, yeast, which form a large number of dairy, acetic acid, ethyl alcohol, carbon dioxide, ethers, giving fermented products pleasant taste and aroma.

Storage pickled vegetables and fruits at a low temperature (about + 3 ° C) helps to preserve their quality.

8) Microbiology of grain products.

Groats, flour are mainly seeded with bacteria, mold fungi, yeast up to 1 million cells per 1 g of food.

Getting from soil, dust, fungal spores are well preserved even with low moisture content of cereals and flour (up to 15%), without affecting the quality of products. When grain products are moistened, mold spores germinate, develop, destroying carbohydrates, proteins, fats of cereals and flour, an unpleasant taste, smell and lumpiness of these products appear. Lactic acid bacteria cause flour to become acidic.

Bread and bakery products are produced using yeast and lactic acid bacteria, which provide the porosity of the bread due to the resulting carbon dioxide, taste and aroma due to the resulting lactic acid, alcohol, ethers and other substances.

Microorganisms that enter the dough with flour, from the air, from equipment, die when baking products, but their spores remain and further spoil the quality of bread if the sanitary and hygienic rules for storing it are violated.

Ready baked bread at high humidity and storage temperatures can additionally be contaminated with microorganisms and spoil in the form of potato, chalk diseases, mold.

Questions for self-control

1. Microbiology of meat and meat products.

2. Microbiology of fish and fish products.

3. Microbiology of sterilized canned food.

4. Microbiology of milk and dairy products.

5. Microbiology of edible fats.

6. Microbiology of eggs and egg products.

7. Microbiology of vegetables, fruits and products of their processing.

8. Microbiology of grain products.

Foods are most susceptible to microbial spoilage due to their favorable chemical composition and high water content.

The composition of the microflora depends on the sanitary state of the enterprise, the conditions of its production, transportation, storage, sale.

Types of spoilage food products:

• licking;

  acidic fermentation;

  pigmentation;

• rancidity;

  self-maturation;

  microbiological diseases;

  swelling.

Microflora of meat and meat products.

Meat is a good nutrient substrate and spoils quickly. Int. layers of meat of a healthy animal after slaughter are not microbes.

The microflora of the meat surface depends on:

animal skins;

slaughter conditions;

primary processing of carcasses;

touching contaminated instruments;

air purity.

On 1 cm 2 there can be 10 2 - 10 3 m / o.

Meat can be infected with gram. (gr -) and gr + BGKP, lactic acid, yeast, mold.

Meat can be contaminated with toxic bacteria.

Microbes penetrate into the meat through blood vessels and mymph. vessels.

Disease is expressed in the formation of a continuous layer of mucus on the surface of the meat bone. This occurs in high humidity environments.

Acidic fermentation.

Often occurs due to poor exsanguination of the animal.

Dark spots.

Minced sausage is more salted than all meat products.

Microbiology of eggs.

Eggs are good nutrient substrates for m / o.

Fresh eggs are obtained from healthy birds.

Eggs: table and dietetic.

The main pathogens for the microflora of eggs are: Escherichia coli, Staphylococcus aureus, moldy fungi.

With prolonged or improper storage, the integrity of the egg shells is violated and it can undergo microbiological deterioration.

Ammonia and hydrogen sulfide accumulate inside the egg. Often, the protein may not be realized with the yolk.

Waterfowl eggs may contain salmonemeosis.

Milania contains a significant number of microbes, therefore, milania breeding is better than depletion. within a few hours.

Microflora of milk and dairy products.

The quantitative and qualitative composition of milk microflora is diverse and depends on the frequency of animal skins, milk, milking machines, air and the frequency of premises. Milk obtained even in unsanitary conditions can contain up to thousands of cells per 1 ml 2. These are mainly staphylococci, lactic acid streptococci, bacteria of the Escherichia coli group (BGKP), causative agents of infectious diseases can be found.

Most bacteria are in summer and autumn. Fresh milk contains substances - laptins, which in the first hours of their life, delaying the development of infectious diseases in milk.

The period of time during which the bactericidal properties of milk have been preserved is called the bactericidal phase.

The bactericidal capacity of milk decreases over time, the higher the temperature in the milk, the more bacteria. When spoiled, curd products will swallow, lick, acquire a sour smell.

Kefir and curdled milk exfoliate, and an unpleasant odor prevails.

Microbiology of fruits and vegetables.

Fruits and vegetables are usually inseminated with microbes. They are living organisms and even breathe and evaporate water as part of suspended animation.

As the fruit is structured, the appearance deteriorates, taste is lost and the nutritional value... The resistance of microbes is explained by the fact that:

1) high acidity;

2) the presence of glycosides;

3) essential oils;

4) tannins;

5) phytoncides;

An important role is played by harmful pathogens formed on the surface of fruits and vegetables. The microflora of sauerkraut is represented by lactic acid bacteria. In the deeper layers, oily acid bacteria can develop.

Microflora of grain and flour.

Microflora is represented by bacteria and moldy fungi, much less yeast, spores of fungi are constantly found, which retain their viability for years.

Oyster microflora

is formed due to the ingress of microbes from sea water or from the hands of equipment personnel.

Molluscs, due to the high content of water and complex proteins, are even more vulnerable to rotting.

Possible cases of typhoid fever and digestive poisoning as a result of eating them raw.

TOPIC: HEALTHY PERSON'S BODY MORPHOLOGY

In a broad sense - the doctrine of the structure of the human body in connection with its development and life; includes human anatomy, embryology and histology. 2) In a narrow sense, a section of anthropology that studies variations in age and sex, ethnoterritorial, constitutional, professional and other features of the human body, as well as its individual parts and organs. Methods of morphological research are used in ethnic anthropology and in the study of anthropogenesis. Without morphological data, it is impossible, for example, to correctly determine the degree of similarity and difference between human races, to understand the history of their formation, it is impossible to assess the relationship between modern man and his fossil ancestors. M. h. Is usually divided into two subsections: merology, or anatomical anthropology, which studies the variations and connections of individual organs and tissues, and somatology, which studies the variability and dependence of the characteristics of the structure of the whole body of a living person. In merology, the integuments of the human body, external parts of the sensory organs, viscera, teeth, blood vessels, muscles, skeleton and skull, and the brain are usually considered. The subject of somatology is the analysis of total body dimensions (body length and weight, chest circumference, surface and volume of the body) and their ratios, body proportions, external forms of its individual parts, sexual characteristics, some blood characteristics, constitutional features, etc. In the 1960s – 1970s. age-related M. h. has developed greatly, especially in connection with the problem of acceleration (See Acceleration). The introduction of methods of physical and chemical analysis into the practice of morphological research makes it possible to obtain data on the composition of the body, i.e. about the tissue components that make up the body of a living person. The relationship of morphological features with biochemical, physiological, endocrinological characteristics, genetics of morphological features, the influence of environmental factors on a person's morphotype are also studied. These morphologies are widely used in anthropological standardization and ergonomics, for example, in the construction of size and growth standards for maximum satisfaction of the population with consumer goods, as well as for the rational arrangement of the workplace, etc.

TOPIC: DISTRIBUTION OF M / O IN NATURE

The relationship of microorganisms with each other and with the environment studies ecology... The basic unit in ecology is ecosystem... It includes both biological and abiotic components. Biotic components constitute a community of organisms, or biocenosis... The sizes of microbial ecosystems are very diverse. This can be, for example, a pond, lake or human body.

The natural habitats of most organisms are water, soil and air. In habitats, microorganisms form microcenoses- communities with specific and often unusual relationships. Each microbial community in a particular cenosis forms specific autochthonous microorganisms, usually found in them. In natural biocenoses (soil, water, air), only those microorganisms that are favored by the environment survive and multiply; their growth stops as soon as environmental conditions change.

Many food products are a favorable environment not only for preservation, but also for the reproduction of microorganisms.

The entire microflora of food products is conventionally divided into specific and non-specific.

The specific microflora includes strains of microorganisms used in the process technological production food products (lactic acid products, bread products, beer, wine, etc.).

Non-specific microflora includes random microflora that gets into food products during their procurement, delivery, processing and storage. The source of these microbes can be raw materials, air, water, equipment, animals, people.

Infection of food with microorganisms can lead to the emergence of food toxicoinfections and other diseases in people.

Microbiological food safety criteria are divided into four groups:

Sanitary indicative microorganisms: BGKP, while taking into account bacteria of the genus Escherichia, Klebsiella, Citrobacter, Enterobacter, Serratia.

Potentially pathogenic microorganisms: coagulase-positive staphylococci, bacteria of the genus Proteus, sulfite-reducing clostridia, B. cereus.

Pathogenic microorganisms, including salmonella.

Microorganisms - indicators of the microbiological stability of the product (yeast, mold fungi).

Sanitary and bacteriological examination of food products

Sampling... Sampling is carried out sterile, with sterile devices, in sterile containers. The samples are placed in an appropriate container and sealed. Transportation is carried out in refrigerated bags as soon as possible.

Sanitary and microbiological assessment of food products includes the determination of the total microbial number and titer of sanitary indicative microorganisms.

Determination of the total microbial count (TMC)

TMC - the total number of microorganisms contained in 1 g (cm 3) of the product. To determine it, use the method of multiple dilutions.

Multiple dilution method... When studying dense substrates, a sample is ground in a homogenizer or ground in a mortar with quartz sand and the initial suspension is prepared at a dilution of 1:10. A series of subsequent dilutions is prepared from the resulting suspension or starting liquid material so that when the last two dilutions are inoculated on a Petri dish in agar, from 50 to 300 colonies grow. Of the last two dilutions, 1 cm 3 is added to a cup and 10-15 ml of melted and cooled to 45 ° C MPA is poured. The dishes are incubated at 37 ° C for 48 hours, the number of grown colonies is counted. TMP is determined taking into account the dilution of the test material.

Limiting dilution method (titer). A series of tenfold dilutions are prepared from the initial liquid material until the presence of one bacterial cell can be assumed in the last test tube. Sowing is done in a liquid selective medium, followed by isolation of microorganisms on a solid nutrient medium and studying their characteristics.

The titer is taken as the smallest amount of substrate in which one individual of the desired microorganism is found.

Determination of sanitary indicative microorganisms

Sanitary indicative microorganisms characterize the product in terms of epidemic hazard.

The main sanitary-indicative microorganisms are considered to be BGKP, and methods for determining the amount and titer are used for quantitative accounting. At the same time, the quantity is understood as the determination of the most probable number (NHF) of BGKP per unit of mass or volume of the product.

Determination of NHF BGKP.

To determine the NSP from a liquid product or a dense initial suspension, dilutions of 10 -1, 10 -2, 10 -3 are successively made, of which 1 cm 3 is inoculated into three test tubes with Kessler's medium for each dilution. After 24 hours of incubation at 37 ° C, changes in the color of the medium and gas formation are recorded in the test tubes. Depending on the number of germinated tubes, the NMF of coliform bacteria is determined.

Determination of the titer of BGKP

Tenfold dilutions of the analyzed material are prepared and plated on Kessler's medium to identify the smallest amount of product in which Escherichia coli is present. The inoculations are incubated at 43 ° C for 18-24 hours. Each tube is inoculated onto Petri dishes with Endo medium so as to obtain the growth of individual colonies. The inoculations are incubated at 37 0 C - 18-24 hours, after which smears are made from the grown colonies, stained according to Gram. If gram-negative rods are detected in smears, colonies are subcultured on Giss media with glucose. The presence of gas formation in test tubes with crops indicates the presence of BGKP.

The titer is set according to the smallest amount of the product in which BGKP is found or according to standard tables.

In assessing food products for microbiological indicators, it is necessary to take into account the possibility of detecting pathogenic and opportunistic microorganisms. Food is analyzed for the presence of salmonella, sulfite-reducing clostridia, staphylococcus, and proteus. In a broader study, products are tested for fungal flora.

To test for Salmonella, a suspension is prepared from the analyzed products and inoculated on storage media (selenite, magnesium chloride broths). After a 24-hour incubation at 37 ° C, subculture is performed on Endo, Levin, Ploskirev media or bismuth-sulfite agar. Further, the colonies are identified by taking into account the growth characteristics on the media of Giss, Ressel, Olkenitsky and in the agglutination reaction with monoreceptor sera.

To identify sulfite-reducing clostridia, the test material is inoculated into 2 test tubes with Kitt-Tarozzi, Wilson-Blair or casein-mushroom medium. One test tube is heated at 80 ° C to destroy the accompanying microflora. Crops are incubated at 37 0 С for 5 days. In the presence of a characteristic growth, it is enough to ascertain the specific microflora in smears and, if necessary, to check the formation of toxins in a bioassay on white mice.

To identify staphylococci, the test material is inoculated on yolk-salt agar. The inoculations are incubated in a thermostat for 24 hours. Colonies suspected of staphylococci are stained according to Gram, they are subcultured onto milk agar and further identification of the isolated culture is carried out.

To identify Proteus, the test material is inoculated onto a slant agar by the Shukevich method. After a 24-hour incubation, smears are made from the upper edge of growth, and if there are gram-negative polymorphic bacteria in them, a conclusion is made about the isolation of Proteus, if necessary, biochemical and antigenic typing is used.

Many food products are a favorable environment not only for preservation, but also for the reproduction of microorganisms.

The entire microflora of food products is conventionally divided into specific and non-specific.

The specific microflora includes strains of microorganisms used in the process of technological production of food (lactic acid products, bread products, beer, wine, etc.).

Non-specific microflora includes random microflora that gets into food products during their procurement, delivery, processing and storage. The source of these microbes can be raw materials, air, water, equipment, animals, people.

Infection of food with microorganisms can lead to the emergence of food toxicoinfections and other diseases in people.

Microbiological food safety criteria are divided into four groups:

1. Sanitary indicative microorganisms: BGKP, taking into account bacteria of the genus Escherichia, Klebsiella, Citrobacter, Enterobacter, Serratia.

2. Potentially pathogenic microorganisms: coagulase-positive staphylococci, bacteria of the genus Proteus, sulfite-reducing clostridia, B. cereus.

3. Pathogenic microorganisms, including salmonella.

4. Microorganisms - indicators of the microbiological stability of the product (yeast, mold fungi).

Sanitary and bacteriological examination of food products

Sampling... Sampling is carried out sterile, with sterile devices, in sterile containers. The samples are placed in an appropriate container and sealed. Transportation is carried out in refrigerated bags as soon as possible.

Sanitary and microbiological assessment of food products includes the determination of the total microbial number and titer of sanitary indicative microorganisms.

Determination of the total microbial count (TMC)

TMC - the total number of microorganisms contained in 1 g (cm 3) of the product. To determine it, use the method of multiple dilutions.

Multiple dilution method... When studying dense substrates, a sample is ground in a homogenizer or ground in a mortar with quartz sand and the initial suspension is prepared at a dilution of 1:10. A series of subsequent dilutions is prepared from the resulting suspension or starting liquid material so that when the last two dilutions are inoculated on a Petri dish in agar, from 50 to 300 colonies grow. Of the last two dilutions, 1 cm 3 is added to a cup and 10-15 ml of melted and cooled to 45 ° C MPA is poured. The dishes are incubated at 37 ° C for 48 hours, the number of grown colonies is counted. TMP is determined taking into account the dilution of the test material.

Limiting dilution method (titer). A series of tenfold dilutions are prepared from the initial liquid material until the presence of one bacterial cell can be assumed in the last test tube. Sowing is done in a liquid selective medium, followed by isolation of microorganisms on a solid nutrient medium and studying their characteristics.

The titer is taken as the smallest amount of substrate in which one individual of the desired microorganism is found.

Determination of sanitary indicative microorganisms

Sanitary indicative microorganisms characterize the product in terms of epidemic hazard.

The main sanitary-indicative microorganisms are considered to be BGKP and methods for determining the amount and titer are used for quantitative accounting. At the same time, the quantity is understood as the definition of the most probable number (NHF) of BGKP per unit of mass or volume of the product.

Determination of NHF BGKP.

To determine the NSP from a liquid product or an initial dense suspension, dilutions of 10 -1, 10 -2, 10 -3 are successively made, of which 1 cm 3 is inoculated into three test tubes with Kessler's medium for each dilution. After 24 hours of incubation at 37 ° C, changes in the color of the medium and gas formation are recorded in the test tubes. Depending on the number of germinated tubes, the NMF of coliform bacteria is determined.

Determination of the titer of BGKP

Tenfold dilutions of the analyzed material are prepared and plated on Kessler's medium to identify the smallest amount of product in which Escherichia coli is present. The inoculations are incubated at 43 ° C for 18-24 hours. Each tube is inoculated onto Petri dishes with Endo medium so as to obtain the growth of individual colonies. Inoculations are incubated at 37 0 C - 18-24 hours, after which smears are made from the grown colonies, stained according to Gram. If gram-negative rods are detected in smears, colonies are subcultured on Giss media with glucose. The presence of gas formation in test tubes with crops indicates the presence of BGKP.

The titer is set according to the smallest amount of the product in which BGKP is found or according to standard tables.

In assessing food products for microbiological indicators, it is necessary to take into account the possibility of detecting pathogenic and opportunistic microorganisms. Food is analyzed for the presence of salmonella, sulfite-reducing clostridia, staphylococcus, and proteus. In a broader study, products are tested for fungal flora.

To test for Salmonella, a suspension is prepared from the analyzed products and inoculated on storage media (selenite, magnesium chloride broths). After a 24-hour incubation at 37 ° C, subculture is performed on Endo, Levin, Ploskirev media or bismuth-sulfite agar. Further, the colonies are identified by taking into account the growth characteristics on the media of Giss, Ressel, Olkenitsky and in the agglutination reaction with monoreceptor sera.

To identify sulfite-reducing clostridia, the test material is inoculated into 2 test tubes with Kitt-Tarozzi, Wilson-Blair or casein-mushroom medium. One test tube is heated at 80 ° C to destroy the accompanying microflora. Crops are incubated at 37 0 С for 5 days. In the presence of characteristic growth, it is enough to ascertain the specific microflora in smears and, if necessary, to check the formation of toxins in a bioassay on white mice.

To identify staphylococci, the test material is inoculated on yolk-salt agar. The inoculations are incubated in a thermostat for 24 hours. Colonies suspected of staphylococci are stained according to Gram, they are subcultured on milk agar and further identification of the isolated culture is performed.

To identify Proteus, the test material is inoculated on a slant agar by the Shukevich method. After a 24-hour incubation, smears are made from the upper edge of growth, and if there are gram-negative polymorphic bacteria in them, a conclusion is made about the isolation of Proteus, if necessary, biochemical and antigenic typing is used.

Microflora of medicinal plants,