Pathogenic microorganisms including salmonella cells. Microbiological studies and assessment of the sanitary condition of soils and soils. Statistics of diseases of salmonella infections in Russia

70% of semi-finished poultry products on store shelves do not meet safety requirements. In addition to pathogenic microflora, salmonella was found in 14 out of 47 poultry meat samples.

Disturbing "still life"

Studies of 47 samples of semi-finished poultry meat products on the instructions of the St. Petersburg Public Organization "Public Control" were carried out by two state testing laboratories accredited in the GOST R system - the State Institution "St. Petersburg Veterinary Laboratory" and the Federal State Institution "Leningrad Interregional Veterinary Laboratory".

The results did not surprise specialists who deal with salmonellosis almost every day. But for consumers, such a “still life” with “game” infected with pathogenic microflora is unlikely to seem appetizing; rather, it will cause justified anxiety.

“Let’s make a reservation right away: when we name manufacturers of semi-finished products, we in no way hold them responsible for the violations identified,” says Vsevolod Vishnevetsky, chairman of the St. Petersburg Public Organization “Public Control”. - Who is to blame for the fact that products that do not meet safety requirements have ended up on store shelves are the responsibility of the authorized state supervisory authorities to find out. In the meantime, “Public Control” is simply stating a fact: dangerous food products have been identified on sale. Damage could occur at any stage: production, warehouse, transportation, deboning (cutting up carcasses) at the wholesaler's base, at a trading enterprise at different stages of the movement of goods.

Presumably, only one conclusion can be drawn so far: the retail enterprises that sold unsafe food products to consumers, namely Okay and Lenta, are to blame. And for this they should be subject to liability measures provided for by law. But this is in theory, when the laws work and control does not sleep. But in life, especially modern Russian life, everything is exactly the opposite. And we have every reason, including documentary ones, to believe that government supervisory authorities will not conduct any inspections. So, dear hypermarkets, you don’t have to worry too much.”

Guilty without guilt?

Among the rejected ones are samples of products from the Roskar poultry farm from the Leningrad region. Chicken wings and thighs produced by St. Petersburg Chicken Company LLC and the Russko-Vysotskaya poultry farm did not pass safety tests. Salmonella bacteria and an excess number of KAMAFanM (total microbial number) were found in products from the Belgorod region (BEZRK Belgrankorm and CJSC TD Prioskolye).

Moreover, at the time of purchasing the products, Lenta LLC did not have accompanying documents confirming the quality and safety of the products for the semi-finished products of the Russko-Vysotskaya poultry farm and the BEZRK Belgrankorm.

Testing laboratories, according to Order No. 189 of the Ministry of Agriculture “On the regulations for the provision of information to the state information support system in the field of agriculture” dated April 2, 2008, were required to urgently transmit all data on products that do not meet safety requirements to higher authorities, as well as to the regions from which the rejected products were delivered. As “Public Control” was assured, this procedure was completed.

Salmonellosis was, is and... will be?

According to the chief specialist of the Veterinary Department for the Leningrad Region, Elena Kryukova, the main sources of salmonellosis in poultry are feed and water. Therefore, the most stringent requirements must be met for water in accordance with SanPiN. And in order to eliminate the presence of pathogenic microflora in poultry feed, it is subjected to heat treatment in feed mills. The Roskar and Severnaya poultry farms have their own feed production sites, where special equipment for disinfection is also installed.

Elena Kryukova emphasizes that sanitary rules and regulations are observed at all poultry farms, and the parent flock is vaccinated. “Otherwise we wouldn’t have such a high level of poultry safety - over 95%,” says Elena Aleksandrovna. “And we would not have taken first place in the country in egg production - 2.6 billion eggs were produced last year, and we would not have held second place in poultry production (the first belongs to the Belgorod region).”

However, the results of the examination of the veterinary department specialists are not surprising. One of the reasons for the detection of salmonella in semi-finished products, in their opinion, is non-compliance with strict temperature conditions during storage and transportation of poultry meat. The optimal temperature for a chicken carcass, both inside and outside, is 2-4 0 C. If the temperature is higher, it is impossible to guarantee 100% safety of poultry meat, especially with the onset of heat and the lack of properly functioning refrigeration equipment, both in carrier vehicles and in retail networks.

Contamination is possible at any stage

The head of the Veterinary Department of St. Petersburg, Yuri Andreev, confirmed that no matter how interested trade and producers are in product safety, individual batches of poultry meat contaminated with pathogenic organisms can still end up on the consumer’s table. In the first quarter of 2011 alone, the veterinary inspection service destroyed 66.5 tons of products that did not meet safety requirements for microbiological indicators; 9.5 tons were disposed of (processed into meat and bone meal).

“We must understand that contamination with salmonellosis pathogens could occur at any stage of food circulation: from cultivation and slaughter to transportation and sale in the retail chain,” says Yuri Aleksandrovich. “Violations of sanitary and hygienic norms and rules, violation of the conditions of storage and movement of products are possible everywhere.”

Deputy Director of the Federal State Institution “Interregional Leningrad Veterinary Laboratory” Jamile Mamleeva and Director of the State Institution “St. Petersburg City Veterinary Laboratory” Anatoly Yashin, responsible for conducting the tests, agree with their colleague. They add on their own that salmonella infection could also occur during the deboning process, where whole carcasses are cut up.

The consumer is not an expert

According to Doctor of Medical Sciences, Academician of MANEB, Professor of the Department of Food Hygiene and Dietetics of the Academy. I.I. Mechnikov Viktor Zakrevsky, every year in developed countries, including Russia, millions of cases of salmonellosis are registered. The main culprits for this are meat, including poultry, milk and dairy products, fish, mayonnaise, and sauces. Essentially, these are the foods that we consume every day and cannot give up.

In addition, Viktor Zakrevsky focuses on the fact that contamination with salmonella does not change the organoleptic properties of the product (taste, color, smell, consistency). Therefore, it is impossible for the consumer to independently determine whether poultry meat is safe for consumption or not.

According to Polina Gunkova, Deputy Dean of the Faculty of Food Technologies, Associate Professor of the Department of Organic, Physical, Biological Chemistry and Microbiology of St. Petersburg State University of Low-Temperature and Food Technologies (SPB GUNIPT), Salmonella bacteria can be destroyed by boiling, but it should be more intense. If we usually cook chicken for 40-60 minutes, then in order to exclude the presence of salmonella bacteria, it is necessary to cook it for 1.5-2 hours, which will inevitably lead to a change in the familiar taste of chicken meat and a decrease in its nutritional properties. But cooking a chicken carcass in a microwave oven does not at all guarantee that pathogenic microorganisms will die completely.

Polina Gunkova explains that in the first hours, meat obtained from a healthy bird is sterile. Microorganisms begin to multiply only after a certain time. Their quantity directly depends on storage conditions and compliance with sanitary standards and temperature conditions. It is possible that personnel could serve as a transmitter of bacteria, but there is a high probability that the bird itself was sick.

“A high CMAFanM (total microbial count) may also indicate that the bird was sick during life,” says the scientist. - In any case, a high total microbial count indicates that the meat has begun to spoil. The vital activity of any bacteria always leads to a change in the physical and chemical parameters of the product (primarily to the decomposition of protein), which cannot be eliminated by any heat treatment,” the expert emphasizes.

Specialists from laboratories conducting research on poultry meat stated that a number of samples did not meet the requirements for organoleptic indicators. In particular, after pressing with a finger, the resulting hole is leveled out slowly, the smell is not characteristic of fresh poultry meat, the muscles on the cut are wet and sticky, and the broth prepared from the samples is slightly cloudy with a slight unpleasant odor.

Polina Gunkova notes that, firstly, this may be evidence that putrefactive processes have begun, and, secondly, the meat could be frozen and subject to thawing. Polina Isaevna emphasizes that a frozen product is potentially more dangerous, since after thawing the microflora begins to multiply at double the speed.

The scourge of poultry farms

Experts who spoke with a PK correspondent openly say that salmonellosis is the scourge of poultry farms not only in Russia, but throughout the world. The interlocutors expressed the hope that the results of the “Public Control” examination will encourage all interested parties to conduct additional checks in order to improve product safety.

At the same time, Professor Zakrevsky draws our attention to the fact that the pathogenic bacterium salmonella is normalized! In 25 grams or less of poultry meat, the presence of pathogenic microorganisms, including salmonella, is not allowed. But if salmonella is found in more quantities of a product, it will be considered safe. “This is a forced measure,” says Viktor Veniaminovich. - Otherwise, you and I would have to give up consuming poultry meat altogether. After all, salmonella is almost always present in poultry meat.”

The state supervision authority refused to check

According to Vsevolod Vishnevetsky, chairman of the St. Petersburg public organization “Public Control”, the only organization that refused to comment on the protocols with the results of testing semi-finished poultry meat products issued by state accredited laboratories was the Office of Rospotrebnadzor for the city of St. Petersburg. The editors' request, sent on May 18, did not receive a response.

However, concrete actions by officials did not follow after they received an official request from the St. Petersburg Public Organization “Public Control” with copies of test reports attached, which established a legal fact: a number of samples of the tested products do not meet safety requirements.

The department, represented by Deputy N. S. Bashketova, refused to carry out an inspection of the violations specified in the protocols of the Federal State Institution "Leningrad Interregional Veterinary Laboratory" and the State Institution "St. Petersburg City Veterinary Laboratory", under the pretext of the absence in the protocols of details of product manufacturers, selection time and delivery time samples, lack of information about delivery conditions. Also, officials were unable to discern which organization carried out the sampling.

And this is despite the fact that the protocols indicate in black and white who exactly delivered the samples - St. Petersburg OOP “Public Control”, the time of selection is indicated in cash and sales receipts (the Office could request them, if this is so important), and the time of delivery of the samples indicated in the protocols of the State Institution “St. Petersburg City Veterinary Laboratory” - 15.20. Moreover, all protocols clearly indicate the source of distribution of semi-finished products: the names of stores with exact addresses!

But if officials have no desire to fulfill their direct duties, you can come up with a bunch of excuses, even this: “Microbiological indicators relate to food safety indicators... and are not the subject of inspection by public organizations in accordance with Art. 45 of the Law of the Russian Federation dated 02.02.1992 No. 2300-1 “On the protection of consumer rights.”

Well, firstly, the law was signed not on the second, but on the seventh of February! Anyway. Secondly, in the mentioned Art. 45 of the law spells out in black and white the rights of public associations of consumers, including: “to conduct an independent examination of the quality and safety of goods...”.

And thirdly, the leaders of the supervisory authority, in addition to the law “On the Protection of Consumer Rights,” should remember well No. 52-FZ of March 30, 1999, “On the sanitary and epidemiological welfare of the population.”

Article 8 of the law states: “Citizens have the right: to exercise public control over the implementation of sanitary rules.” Article 52 directly obliges officials carrying out state sanitary and epidemiological supervision to “consider appeals from citizens and legal entities on issues of sanitary and epidemiological well-being of the population and take appropriate measures; carry out its activities to ensure the sanitary and epidemiological well-being of the population in cooperation with... public associations; provide assistance to public associations in matters of ensuring the sanitary and epidemiological well-being of the population and the implementation of sanitary legislation.”

Indeed, legal requirements are compensated by the optionality of their implementation. Alas, our officials seem to have firmly grasped this “law.”

Once, speaking at a meeting of the Russian government on the organization of state supervision and control, its chairman Vladimir Putin said: “It is obvious that today most control procedures, unfortunately, are again of a purely formal nature. These are, as a rule, checks without any checks or they are a tool “for extorting bribes.” This state of affairs, of course, cannot suit either citizens, business representatives, or the state. And if we want to improve the business climate, and we must do this, if we want to stimulate medium and small businesses, we need to change the procedures, and most importantly, the content of control and supervision itself... Finally, supervisory authorities should be aimed at preventing real threats, at protecting life and health of people, in order to protect our market from low-quality and sometimes dangerous goods and services.”

“This was said a year and a half ago,” notes Vsevolod Vishnevetsky. - Unfortunately, little has changed in the system of government supervision and control since then. And it is unlikely to change in the near future as long as the interests of the bureaucracy and big business remain above the interests of the ordinary citizen.”

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(lat. Salmonella) - a genus of bacteria, facultative anaerobes.

Salmonella classification

According to modern concepts, the genus Salmonella includes 2 species: Salmonella bongori And Salmonella enterica. View Salmonella enterica includes 7 subspecies: I enterica, II salamae, IIIa arizonae, IIIb diarizonae, IV houtenae, VI indica and VII, each of which has many serotypes.

Many serotypes Salmonella enterica- pathogens of human diseases, including typhoid fever, paratyphoid fever, salmonellosis. Salmonella species Salmonella bongori not pathogenic for humans.

Subspecies Salmonella enterica enterica includes the following serogroups:

• A (best known serotype paratyphi A)
• B (serotypes: typhimurium, agona, derby, heidelberg, paratyphi B and etc.)
• C (serotypes: bareilly, choleraesuis, infantis, virchow and etc.)
• D (serotypes: Dublin, enteritidis, typhi and etc.)
• E (best known serotype anatum)

Salmonella. General information

Salmonella grows at temperatures from +35 to +37 ºС, but is able to survive at temperatures from +7 to +45 ºC and acidity from 4.1 – 9.0 pH. Salmonella are relatively stable in the external environment: they persist in room dust for up to three months, in open water from 11 to 120 days, in meat and sausages from two to six months, in frozen meat from six months to a year or more, in in milk at room temperature for up to 10 days, in milk in the refrigerator for up to 20 days; in butter - 52–128 days; in eggs - up to a year or more, on eggshells - from 17 to 24 days. At 70° C, salmonella die within 5–10 minutes; in the thickness of a piece of meat, boiling is maintained for several hours. In meat stored in the refrigerator at low above-zero temperatures, salmonella not only survive, but are also able to multiply.

Salmonella - pathogens of human diseases

• Salmonella enterica enterica serotype typhi(often written simply Salmonella typhi) - the causative agent of typhoid fever
• Salmonella enterica enterica serotypes paratyphi A, paratyphi B, paratyphi C(or Salmonella paratyphi A etc.) - pathogens of paratyphoid A, B and C
• Salmonella enterica enterica, various serotypes: agona, enteritidis, typhimurium, heidelberg, newport and others - pathogens of salmonellosis.

The cause of salmonellosis is most often eggs containing salmonella (up to 90% of salmonellosis cases are associated with the consumption of raw or insufficiently cooked eggs), meat and dairy products, and, to a lesser extent, fish and fish products, as well as products of plant origin. The natural reservoir of salmonella is poultry and animals: ducks, chickens, cattle, pigs, sheep. Salmonella contamination of meat occurs after slaughter, when the rules for cutting and storing meat are violated. Salmonella often gets into food due to improper cooking or failure to comply with sanitary standards when preparing it.

Salmonella can cause various diseases of the human genitourinary organs, in particular prostatitis, cystitis and pyelonephritis.

See more details: Salmonella (non-typhoid). WHO Information Bulletin N°139.

Nosocomial infections caused by Salmonella

• surgical intervention (mainly on the abdominal organs) (75–80%)
• treatment and stay in the postoperative period in intensive care and intensive care units (80–85%)
• active therapy with hormones, chemotherapy, antibiotics (100%)
• dysbacteriosis (95–100%)
• elderly patients (more than 75% were people over 68 years old)
• chronic pathology of organs and systems with signs of functional failure (95–98%).

Amphibians and reptiles are the cause of salmonellosis

Salmonella in the USA

For details, see "Salmonella in the USA". See also: "Advice from the American College of Gastroenterology for Food Poisoning" (translation into Russian of a release published in the USA on June 3, 2011 in connection with the infection in Europe), recommendations of Rospotrebnadzor: “On the prevention of food poisoning and infectious diseases transmitted by food.”

Statistics of diseases of salmonella infections in Russia

In 2012, 30 cases of typhoid fever were recorded in the Russian Federation, in 2013 - 69, in 2014 - 12, in 2015 - 29, in 2106 - 13.

The incidence of salmonellosis in 2012 increased by 1.3% compared to 2011 and amounted to 36.59 per 100 thousand population, in 2013 - 33.65, 2014 - 29.08, in 2015 - 25.39, in 2016 - 26.08.

Antibiotics, active and inactive against salmonella

3.1.1. Concept of food infections and food poisoning

Contamination of food products with microorganisms occurs during their processing and transportation. Sources of microorganisms can be equipment, operating personnel, air, water and auxiliary materials.

The presence of certain microorganisms or their metabolites in food products can cause infectious diseases in humans. Infectious diseases are a broad group of diseases caused by the presence of pathogenic bacteria, viruses, protozoa and helminths.

Independent sections in infectious diseases are:

Diseases caused by bacteria;

Diseases caused by microscopic fungi;

Diseases caused by viruses;

Infectious diseases associated with the consumption of food and caused by bacteria, viruses and microscopic fungi are conventionally divided into two groups:

1 - food infections,

2 - food poisoning.

Foodborne infections (toxicoinfections)- diseases in which the food product is only a transmitter of pathogenic microorganisms; they usually do not reproduce in the product. Foodborne infections are caused by viruses, enteropathogenic Escherichia coli, enterococci, pathogenic halophiles, etc. An example of a food infection is intestinal infections: diphtheria, typhoid fever, paratyphoid fevers A and B, cholera, salmonellosis, brucellosis, viral hepatitis A (Botkin), pseudotuberculosis, etc.; infections of the external integument: anthrax, foot and mouth disease, etc.

Food poisoning, or food intoxication, is usually called a disease when the toxin that causes it is produced by a microorganism growing in food. Pathogenic microbes produce two types of toxins: exotoxins easily pass from the microbial cell into the environment. They affect certain organs and tissues, with characteristic external signs, i.e. have specificity of action; endotoxins are not released from the microbial cell during its life; they are released only after its death.

3.1.2. Classification of food poisoning

According to the classification of food poisoning, adopted in 1981 and based on the etiopathogenetic principle, food poisoning according to etiology(reasons) are divided into 3 groups:

I. Microbial food poisoning:

1. Toxic infections (caused by opportunistic microorganisms): bacteria of the genus E. Coli, Proteus, spore-bearing anaerobes (sulfite-reducing clostridia or Clostridium perfringens), spore-bearing aerobes (Bacilus cereus);

2. Toxicoses (intoxication):

Bacterial toxicoses (St. Aureus and Clostridium botulinum);

Mycotoxicoses (molds: Aspergillius, Fusarium, etc.);

3. Mixed etiology or mixed (combination of microorganisms).

II. Non-microbial food poisoning:

1. Poisoning with poisonous plants and animal tissues:

a) Plants that are poisonous by nature:

Poisonous mushrooms (pale toadstool, fly agaric, etc.); conditionally edible mushrooms that have not been subjected to proper heat treatment (milk mushrooms, tremulous mushrooms, volui, morels, etc.); wild and cultivated plants (belina, poisonous wech, datura, elderberry, belladonna, etc.);

Wild plants (henbane, datura, hemlock, belladonna, etc.); seeds of weeds, cereals (Sophora, Trichodesma, heliotrope, etc.).

b) Animal tissues that are poisonous by nature:

Organs of some fish (barbel, marinka, pufferfish, Sevan chromulya),

Some endocrine glands of slaughter animals (adrenal glands, pancreas, etc.).

2. Poisoning with products of plant and animal origin, poisonous under certain conditions:

a) Plant origin:

Kernels of stone fruits (peaches, apricots, cherries, almonds) containing amygdalin; nuts (beech, tung, etc.); raw beans containing phasin; sprouted green potatoes containing solanine.

b) Of animal origin:

Liver, caviar, milt of some species of fish during the spawning period (pike, burbot, mackerel, tuna, etc.); mussels; honey when bees collect nectar from poisonous plants.

3. Poisoning due to chemical impurities:

Pesticides, nitrates, biphenyls; salts of heavy metals; unauthorized food additives; substances migrating from equipment, packaging, etc.; other impurities (hormones, antibiotics, etc.).

III. Unknown etiology:

Alimentary paroxysmal toxic myoglobinuria (Haffian, Yuksovsky, Sartland disease as a result of eating lake fish in some areas of the world in some years.

Food poisoning and foodborne infections are the most serious and common food-related hazards. When assessing the safety of food raw materials and food products, microbiological criteria are first determined.

Hygienic standards for microbiological indicators include control over 4 groups of microorganisms:

Sanitary indicators, which include mesophilic aerobic and facultative anaerobic microorganisms - MAFAM and bacteria of the Escherichia coli group - coliforms (coliforms);

Opportunistic microorganisms, which include E.coli, S.aureus, bacteria of the genus Proteus, B.cereus and sulfite-reducing clostridia;

Pathogenic microorganisms, including salmonella;

Spoilage microorganisms- These are mainly yeasts and molds.

Food safety assessment is carried out based on the standardized mass of the product, in which the presence of coliform bacteria, most opportunistic microorganisms, and pathogenic microorganisms is not allowed. In other cases, the standard reflects the number of colony-forming units in 1 g or 1 ml of products (CFU/g, ml).

3.1.3. Characteristics of foodborne infections

and bacterial poisonings

An example is staphylococcal food poisoning. Caused by an enterotoxin produced by the bacterium Staphylococcus aureus (S. aureus) during its growth in food products. Developing in food products, it can release a special type of toxin - enterotoxin, which affects the human intestines. Six enterotoxins have been identified: A, B, C, D, E and F. Two forms of enterotoxin C have been isolated and obtained - C 1 and C 2. Staphylococci are spherical bacteria (cocci), gram-positive bacteria.

The bacterium is resistant to heat, remains active at 70 °C for 30 minutes, at 80 °C for 10 minutes. S. aureus enterotoxins are even more resistant to heat; final inactivation occurs only after 2.5-3 hours of boiling. S. aureus is resistant to high concentrations of table salt and sugar. The vital activity of the bacterium ceases when the concentration of sodium chloride in water is more than 12%, sugar - 60%, which must be taken into account when preserving food products. At temperatures up to 4-6 °C, the reproduction of S. aureus also stops. The optimal temperature for the proliferation of staphylococci is 22-37 °C.

The source of infection can be both humans and farm animals. Through the latter, mainly milk, meat and their processed products are infected. In humans, staphylococcal infection is localized on the skin, nasopharynx, intestines, and other organs and tissues.

Getting into food raw materials, food products and culinary products, staphylococci produce toxins with varying intensity, depending on the level of contamination, time and temperature of storage, characteristics of the chemical composition of the contaminated object (content of proteins, fats, carbohydrates, vitamins, pH of the environment, etc. ). The most favorable environment for the life of bacteria is milk, meat and their processed products, therefore it is these food products that most often cause staphylococcal poisoning.

Milk and dairy products. Contamination of milk with staphylococci can occur from cows with mastitis, through contact with the skin of sick animals and people involved in milk processing. It has been noted that staphylococci multiply and produce enterotoxins in raw milk weaker than in pasteurized milk, since they are a poor competitor in the fight against other milk microorganisms. This explains the absence of enterotoxins and staphylococci in fermented milk products for which active milk cultures are used for fermentation. In addition, lactic acid formed during the production of these products inhibits the proliferation of these microorganisms.

Once in milk, staphylococcus begins to produce enterotoxins at room temperature after 8 hours, at 35-37 ° C - within 5 hours. When young cheese is contaminated with staphylococci, enterotoxins are released on the 5th day of its ripening at room temperature. After 47-51 days of storage of cheese, staphylococci die, while enterotoxins persist for another 10-18 days.

Enterotoxins can be found in other dairy products if these products were made from milk and infant formulas contaminated with staphylococci.

Meat and meat products. Contamination of meat with staphylococci occurs during the slaughter of animals and processing of raw materials. As in raw milk, competing microflora prevents these bacteria from rapidly multiplying in raw meat. Under certain technological conditions, especially when competing microflora are eliminated, staphylococci can actively multiply in meat products and produce enterotoxins.

In minced meat, raw and cooked meat, staphylococci produce toxins under optimal conditions (22-37 °C) after 14-26 hours. Adding white bread to minced meat increases the rate of formation of toxic metabolites by 2-3 times. The salt concentration used for brining does not inhibit S. aureus; The pH of meat and meat products, which prevents the development of bacteria, should be no higher than 4.8. Smoking sausages at a certain temperature promotes the growth of staphylococci. In finished cutlets, after seeding, enterotoxins are formed after 3 hours, in liver pate after 10-12 hours. Vacuum packaging of meat products inhibits the growth of staphylococci.

The data described above is typical for poultry meat. Staphylococci do not penetrate or grow in whole raw eggs. When eggs are cooked, their bacteriostatic properties are destroyed, and they can become infected with staphylococci as a result of washing and storage.

Other food products. A favorable environment for the reproduction of S. Aureus is flour confectionery products with custard. When the cream is contaminated at a temperature favorable for bacteria (22-37 °C), the formation of toxins is observed after 4 hours. The sugar concentration in such products is usually less than 50%; Sugar content of 60% or higher inhibits the formation of enterotoxins.

Symptoms Staphylococcal intoxication in humans can be observed 2-4 hours after consuming enterotoxin. However, initial signs may appear after 0.5 and 7 hours. Initially, salivation is observed, then nausea, vomiting, and diarrhea. The disease is sometimes accompanied by complications: dehydration, shock, and the presence of blood or mucus in the stool and vomit.

Other symptoms of the disease include headache, cramps, sweating and weakness.

Recovery often occurs within 24 hours, but may take several days. Deaths due to food poisoning are rare.

Prevention measures:

1. Do not allow people who are carriers of staphylococci (with pustular diseases, acute catarrhal symptoms of the upper respiratory tract, dental disease, nasopharynx, etc.) to work with food raw materials and food products.

2. Ensuring sanitary order in the workplace.

3. Compliance with technological regimes for food production that ensure the death of staphylococci. Heat treatment and storage temperature of raw materials and finished products are of decisive importance.

Clostridium perfringens- spore-forming anaerobic gram-positive bacteria, widespread in nature due to their resistance to various influences. Vegetative cells of bacteria look like straight thick rods measuring 2-6 x 0.8-1.5 microns. Six strains of Cl were studied. perfringens: A, B, C, D, E and F, which produce toxins with diverse properties. Food poisoning is caused mainly by strains A and D. The toxicological picture is determined by A-toxin. Clostridium perfringens develops at temperatures from 15 to 50 ° C and pH 6.0-7.5. The optimal temperature of 45 °C and pH 6.5 ensures a generation duration of about 10 minutes. Enterotoxins are released from vegetative cells during the formation of mature spores from these cells. This can occur both in foods and in the human intestine.

The source of the disease is mainly products of animal origin - meat and dairy, the contamination of which occurs both during the life of animals (sick and bacilli-carrying) and after slaughter (in case of violation of sanitary and hygienic standards for processing and storing raw materials). Sources of infection can be fish and seafood, legumes, potato salad, and macaroni and cheese.

After infection enters the body, the incubation period lasts from 5 to 22 hours. Characteristic signs of the disease- diarrhea, cramps and abdominal pain.

Preventive actions provide for compliance with sanitary and hygienic requirements when processing raw materials and storing finished products.

Bacteria of the genus Salmonella. Bacteria of the genus Salmonella belong to the group of pathogenic intestinal bacteria. These are gram-positive, non-spore-forming, short rods.

There are three main types of salmonellosis: typhoid fever, gastroenteritis, and localized type with lesions in one or more organs (septicemia). Each strain of salmonella is capable of causing any of the above clinical types of infection.

80-90% of salmonellosis is caused by four types of these bacteria. Salmonella are characterized by resistance to various physicochemical factors. They grow at temperatures from 5.5 to 45 °C, optimal - 37 °C. They remain viable when cooled to 0 °C for 142 days, at a temperature of 10 °C - 115 days. Heating to 60 °C leads to the death of salmonella after 1 hour, at 70 °C - after 15 minutes, at 75 °C - 5 minutes, and when boiling, instant death occurs.

Bacteria lose their mobility and ability to grow in an environment with an acidity level below 6.0. It has been established that sodium chloride (7-10%), sodium nitrite (0.02%) and sucrose cause a decrease in the viability or death of bacteria.

Contamination of food products with salmonella can occur both through animals and humans.

The main food products that transmit salmonella toxic infections are meat and meat products, the contamination of which is carried out both during the life of animals and after their slaughter.

Animals sick with salmonellosis excrete salmonella in their milk; therefore, milk and dairy products also contribute to the spread of salmonella toxic infections. In addition, salmonella carriers can be food workers who suffer from latent forms of salmonellosis or are bacteria carriers.

A special role in the etiology of salmonellosis is played by intravitally contaminated food products: eggs, meat of ducks, geese, chickens, turkeys.

Prevention measures:

1. The work of the veterinary and sanitary service directly on farms to identify animals and poultry with salmonellosis.

2. Carrying out a sanitary and veterinary examination during the primary processing of raw materials and manufacturing of food products.

It is necessary to comply with sanitary requirements for defrosting meat, store raw materials and semi-finished products at a temperature not exceeding 4-8 ° C, use cold at all stages of the production process, including transportation of raw materials, semi-finished products and finished products, comply with the sales deadlines established for each product, as well as heat treatment modes. The latter is of fundamental importance in the prevention of Salmonella toxic infections, given the destructive effect of heating (at least 80 ° C) on bacteria. The sale of unboiled and unpasteurized milk to the population is not permitted.

3. Implementation of systematic control of rodents as a source of contamination of raw materials and products in food enterprises.

4. Compliance with appropriate sanitary requirements regarding water, ice, equipment, utensils and equipment.

5. At food industry and catering enterprises:

· it is necessary to identify and refer for treatment workers who suffer from salmonellosis or are carriers of the bacteria;

· do not allow such people to work until they have fully recovered;

· register chronic bacteria carriers.

Points 3-5 are important in the prevention of salmonellosis contamination of plant products, although such cases are rare.

Bacteria of the genus Escherichia coli. Pathogenic strains of E. coli are able to multiply in the small intestine, causing toxic infection (the main symptom of the disease is watery diarrhea, leading to dehydration and shock). The source of pathogenic strains can be humans and animals. Products of both animal and plant origin are contaminated. The routes of infection are the same as for salmonellosis.

Prevention measures:

1. Identification and treatment of food enterprise workers who are carriers of pathogenic serotypes of Escherichia coli.

2. Carrying out veterinary supervision of animals. Meat from animals suffering from colibacellosis is considered conditionally suitable and is subject to special heat treatment.

H. Compliance with sanitary standards and technology regimes for the production and storage of food products.

4. Compliance with the sanitary regime at the enterprise (washing and disinfection of inventory and equipment, etc.).

Bacteria of the genus Proteus. The genus Proteus includes five species. The causative agents of food toxic infections are mainly Pg. mirasilis and Rg. vulgaris. The optimal conditions for the development of these bacteria are a temperature of 25-37 °C. They can withstand heating up to 65 °C for 30 minutes, pH in the range of 3.5-12, lack of moisture for up to 1 year, high concentration of table salt - 13-17% for 2 days. All this indicates the resistance of Proteus to external environmental factors.

The causes of Proteus toxicoinfections may be the presence of sick farm animals, the unsanitary condition of food enterprises, and violation of the principles of personal hygiene. The main products through which this disease is transmitted are meat and fish products, and less often potato dishes. There may be cases of contamination of other food products.

Enterococci. Potentially pathogenic strains among enterococci (Streptococcus faecalis) are Str. Faecalis var. Liguefaciens and Str. Faecalis var. Zumogenes. They reproduce at temperatures from 10 to 15 °C. Resistant to drying, low temperatures, can withstand 30 minutes at 60 °C; die at 85 °C for 10 minutes.

Sources of infection are humans and animals. The routes of food contamination are the same as for other types of toxic infections.

Botulism- is a severe food poisoning, often fatal, caused by toxins secreted by Clostridium botulinum. Clostridium botulinum is a strictly anaerobic, rod-shaped, gram-positive bacterium. Seven types of toxins have been studied - A, B, C, D, E, F and G. Botulinum toxins A and E are the most toxic.

Bacteria Cl. botulinum are widely distributed in the environment. They enter the soil in the form of spores when fertilizing it with manure, so plant products become contaminated with spores through the soil.

Spores, in comparison with the vegetative form of Clostridium botulinum, are resistant to physicochemical environmental factors. At 100 °C they remain viable for 360 minutes, at 120 °C - 10 minutes. Spores germinate at sodium chloride concentrations of up to 6-8%. The reproduction of bacteria stops at pH 4.4 and a temperature of 12-10 ° C and below; at 80 ° C they die within 15 minutes. The optimal temperature for the life of Clostridium botulinum is 20-37 °C.

Botulinum toxins are characterized by high resistance to the action of proteolytic enzymes, acids and low temperatures, but are inactivated under the influence of alkalis and high temperatures: at 80 ° C - after 30 minutes, at 100 ° C - after 15 minutes.

The described properties of vegetative forms of Clostridium botulinum, spores and toxins should be taken into account in food manufacturing technology.

Botulism manifests itself mainly by damage to the central nervous system. The main symptoms are double vision, drooping eyelids, choking, weakness, headache. Difficulty swallowing or loss of voice may also occur. The patient's face may lose expression due to paralysis of the facial muscles. Duration of incubation period: 12-36 hours, but can range from 2 hours to 14 days.

Prevention measures:

1. Prevention of contamination of farm animal carcasses with particles of earth, manure, as well as in the process of cutting them - with intestinal contents; ambassador in cold conditions; compliance with heat treatment regimes.

2. Use of fresh plant materials; pre-washing and heat treatment; sterilization of the product to prevent the germination of spores, the proliferation of vegetative forms and the formation of toxins.

Bacteria genus Bacillus cereus cause two types of illness, one characterized by diarrhea and the other by vomiting. Symptoms of the diarrhea form include abdominal pain, watery diarrhea and mild nausea, rarely leading to vomiting. These symptoms rarely last more than 12 hours. The development of the disease, accompanied by vomiting, usually occurs within 1-5 hours after consuming the contaminated product.

Bacteria genus Shigella cause dysentery in humans - ulcerative inflammation of the mucous membrane of the large intestines.

Incubation period: from 2 to 7 days; recovered patients often remain carriers of the bacilli. Some bacillary dysentery epidemics have high mortality rates.

Brucellosis(Brucella), is caused by consuming the milk of sick animals or dairy products. The causative agents of brucellosis are small bacteria Brucella, which belong to facultative anaerobes with an optimal growth temperature of 37 ° C. These bacteria can survive in food products for a long time, they are resistant to drying, and easily tolerate cold.

When heated to 60 °C, brucellosis pathogens die in 10-15 minutes. The disease occurs in the form of fever, joint and muscle pain and can last for several years. With brucellosis, some symptoms of damage to the nervous system are often observed: headaches, dizziness, mental disorders.

Tuberculosis caused by rods called Mycobacterium tuberculosis. Sources of infection are sick humans and animals; infection occurs through the respiratory tract. When consuming contaminated milk and dairy products, tuberculosis infection can occur through the intestines.

The tuberculosis bacillus is the most resistant to adverse physical and chemical environmental factors and can survive for a long time in food products: in cheese for up to 2 months, in fermented milk products for up to 20 days. In milk, the tuberculosis bacillus dies when heated to 100 °C immediately, at 70 °C - after half a minute, at 55 °C - after an hour.

anthrax caused by a large spore-forming bacillus Bac. Anthracis. The optimal growth temperature for these bacilli is 37 °C. The spores are very stable and can withstand prolonged boiling. Human infection occurs through contact with sick animals - cattle, as well as through consumption of contaminated food or water. The disease can develop in three forms: skin, pulmonary and intestinal. Duration of the incubation period: for the skin form - 1-7 days; in the pulmonary form - unknown.

The mortality rate of the disease in pulmonary and intestinal forms is very high, in cutaneous forms it is 5-20%.

When consuming food products contaminated with Vibrio cholerae, severe gastrointestinal disease occurs: cholera . This disease is common in India, Pakistan and parts of China. The disease begins suddenly and is characterized by vomiting, severe diarrhea, muscle spasms, and rapid dehydration. The duration of the incubation period is 1-5 days. The mortality rate of the disease without treatment is 10-80%, with treatment - 5-30%.

Thus, taking into account the degree of hazards of microbiological origin and the need to reduce the level of food poisoning and food infections, the sanitary condition of food enterprises and farms, public catering establishments, workplaces and equipment should be strictly monitored; systematically carry out microbiological control of food raw materials and food products.

Meat and meat products are examined according to GOST 21237--75 to detect contamination with bacteria of the genus Salmonella (as well as opportunistic bacteria, staphylococci and anaerobes).

Pathogenicity of bacteria of the genus Salmonella for animals.

The pathogenic effect of salmonella, like other pathogenic microorganisms, on animals (as well as on humans) manifests itself when complex mechanisms between micro- and macroorganisms are disrupted. The degree of pathogenicity of strains depends on the type of Salmonella, the infectious dose, the biological characteristics of the pathogen, as well as the age of the macroorganism, its resistance and other factors. To date, a sufficient amount of data has accumulated in the literature indicating the inconsistency of distinguishing Salmonella into pathogenic only for humans and animals.

In animals, including birds, under natural conditions, salmonella are causative agents of septic infectious diseases called paratyphoid fever, or salmonellosis. In accordance with pathogenesis and epizootology, these diseases are divided into primary and secondary salimonellosis. In addition, paratyphoid (Salmonella) enteritis of adult cattle is separately distinguished, which may have the nature of a primary or secondary disease, as well as Salmonella carriage in animals.

Primary salmonellosis is a typical infectious disease that is caused by specific pathogens and, during its course, has a certain clinical picture and pronounced pathological changes. Primary salmonellosis includes: salmonellosis (paratyphoid) of calves (pathogens S. dubin, S typhimurium), salmonellosis of piglets (pathogens S typhisuis, S. choleraesuis, less often S. dublin), salmonellosis of lambs (pathogen S. abortusovis), salmonellosis of foals (pathogen S. abortusequi), poultry salmonellosis (pathogen S. typhimurium, less often S. essen, S. anatum), pullorosis-typhoid fever of chickens (pathogen S. qallinarum-pullorum]J

Salmonellosis (paratyphoid) of calves is one of the most common salmonellosis diseases, and in terms of the severity of clinical signs and pathological and anatomical changes, it is classified as “classic”. Calves from 2 weeks to 3-6 months of age, and sometimes even older, are susceptible. The disease, as a rule, has the character of a persistent stall infection and is often acute. Clinically, it manifests itself as weakness, drowsiness and decreased appetite in calves. Body temperature can rise to 41 °C and higher, short-term constipation is replaced by persistent profuse diarrhea, even with an admixture of blood and mucus in the stool. As the disease progresses, rapidly progressive emaciation of calves occurs. Toward the end of the disease, exhaustion, ruffled fur, and sunken eyes into the orbit are observed. In case of prolonged paratyphoid fever, calves develop pneumonia, swelling of the joints occurs, mortality can be 25-30%, and sometimes even up to 60%.

During post-mortem diagnostics, the most characteristic pathological changes are also detected in salmonellosis of calves. These changes are as follows: diffuse catarrhal or catarrhal-hemorrhagic inflammation of the abomasum and intestines, on the mucous membrane of the abomasum and intestines with hemorrhages in them, and lymphatic hyperemia, enlargement of the spleen, hemorrhages on the serous membranes and in the cortical layer of the kidneys. A particularly characteristic sign of salmonellosis in calves is the presence of yellowish-gray necrotic nodules in the liver, which are found both under the serous membrane and on the cut surface of the organ.

Inflammation of the joints with the presence of fibrin flakes in the synovial fluid is often observed. In the lungs, especially in the anterior and middle lobes, dark red pneumonic foci and numerous hepatized areas with small yellowish necrotic foci (pneumonia) are possible. Salmonellosis of calves in some cases is accompanied by yellowness of all tissues. With other salmonellosis, only individual pathological signs are found from the general complex that is revealed during post-mortem examination of the organs of calves sick with salmonellosis. With salmonellosis in pigs, the pathological changes are in many ways similar to those with plague.

Secondary salmonellosis does not represent an independent disease, but occurs in animals (including birds) that carry salmonella during infectious, invasive and non-contagious diseases, poisoning and septic-pyemic processes, prolonged fasting, overwork and other factors that reduce the body’s resistance. Under these factors, the virulence of Salmonella increases, they multiply intensively and penetrate from the places of initial localization (intestines, liver, mesenteric lymph nodes) into various organs and muscles. In this regard, pathological changes can be very diverse and are largely determined by the primary pathological process on which secondary salmonellosis is superimposed. Hemorrhages in various organs, especially in the liver, kidneys and lymph nodes, hemorrhages on the serous membranes, poor bleeding of carcasses, abscesses in the liver, arthritis, fatty degeneration of the liver give reason to suspect secondary salmonellosis. Secondary salmonella diseases of animals are most often encountered in the practice of veterinary and sanitary examination and play a large role in the occurrence of foodborne toxic infections in humans.

Salmonella (paratyphoid) enteritis in adult cattle is caused by S. enteritidis, S dublin, as well as S. typhimurium and can be a primary or secondary disease. The most characteristic pathological signs of this disease are the following: low fatness of carcasses, hyperemia and hemorrhages on the intestinal mucosa, enlargement and blood filling of the spleen with a crimson color of the pulp, enlargement and fragility of the liver, inflammation of the gallbladder, enlargement and hemorrhagic inflammation of the lymph nodes, sometimes single or typical paratyphoid nodules collected in groups, the size of a poppy seed to the head of a pin, and icteric staining of all tissues. The final diagnosis of salmonella diseases, as well as salmonella carriage in animals, is made on the basis of bacteriological examination.

Pathogenicity of bacteria of the genus Salmonella for humans. As stated above, Salmonella do not have enterally acting toxins, and their pathogenicity on the human body is manifested by the combined effect of living microbes and toxins. Once in the gastrointestinal tract with meat and other foods, toxic substances sensitize the intestinal mucosa and disrupt its reticuloendothelial barrier. This contributes to the rapid penetration of Salmonella bacteria into the blood and the development of bacteremia. When bacteria are destroyed in the body, endotoxin is released, which largely determines the clinical picture of toxic infection.

The gastroenteric form is manifested by increased body temperature, chills, nausea, vomiting, loose stools, sometimes mixed with blood and mucus, abdominal pain, increased thirst and headaches. The disease is especially severe, with symptoms of uncontrollable vomiting and even damage to the nervous system, when S. typhimurium enters the human body with food.

The typhoid-like form can begin with ordinary gastroenteritis and, after an apparent temporary recovery, after a few days it manifests itself with signs characteristic of ordinary typhoid fever.

The influenza-like form, quite common in human illness, is characterized by pain in the joints and muscles, rhinitis, conjunctivitis, catarrh of the upper respiratory tract and possible gastrointestinal disorders.

The septic form occurs in the form of septicemia or septicopyemia. In this form, local septic processes caused by Salmonella are observed with localization of foci in internal organs and tissues: endocarditis, pericarditis, pneumonia, cholecystitis, osteomyelitis, arthritis and abscesses, etc.

The mortality rate for salmonella toxic infections averages 1-2%, but depending on the severity of outbreaks, the age composition of people (disease among children) and other circumstances, it can reach up to 5%. Based on literature data, many authors do not consider it correct to call this disease in humans Salmonella toxicoinfection. In their opinion, recognition of the great pathogenetic significance of toxinemia, which is impossible without a living pathogen, does not provide grounds for calling this disease that way. I. S. Zagaevsky and others consider it more correct to call this disease food-borne salmonellosis.

Epidemiology of food salmonellosis. According to domestic and foreign authors, the leading role in the occurrence of food-borne salmonellosis belongs to meat and meat products. Particularly dangerous in this regard is meat and offal (liver, kidneys, etc.) from forcedly killed animals. Intravital contamination of muscle tissue and organs with Salmonella occurs as a result of animal disease with primary and secondary salmonellosis. Dangerous food products from the point of view of the occurrence of foodborne salmonellosis include minced meat, jellies, brawn, low-grade (separate, table, liver, blood, etc.) sausages, meat and liver pates. When grinding meat into minced meat, the histological structure of the muscle tissue is disrupted, and the leaking meat juice contributes to the dispersion of salmonella throughout the entire mass of minced meat and their rapid reproduction. The same applies to pates. Jellies and brawns contain a lot of gelatin, and low-grade sausages contain a significant amount of connective tissue (pH 7.2-7.3). Under these conditions, Salmonella also develops very quickly. Waterfowl are often salmonella carriers, and, therefore, their eggs and meat can be a source of foodborne salmonellosis. Less commonly, Tomsk infections are possible when eating milk and dairy products, fish, ice cream, confectionery (cream pastries and cakes), mayonnaise, salads, etc.

Exogenous contamination of meat and prepared foods with Salmonella should also be taken into account. Sources of exogenous contamination can be various environmental objects: water and ice, containers, knives, tables, production equipment, with the help of which primary processing and processing of products is carried out; The participation of biological agents in the contamination of products with Salmonella (mouse-like rodents, flies) is also not excluded. The contact route of infection with salmonella according to the “animal (bacterium-excreting) – human” scheme is not excluded. Indoor animals (dogs, cats), as well as pigs, poultry and even pigeons play a certain role in this. The contact factor of transmission according to the “person-to-person” scheme is a rare phenomenon and occurs more often in children.

The main characteristics of the genus Salmonella are short gram-negative rods with rounded ends, 1.5-4.0 microns in length, in most cases motile (peritrichs), do not have spores or capsules, and form acid and gas during the fermentation of glucose (and a number of other carbohydrates) ( except S. typhi and some other serotypes), have lysine and ornithine decarboxylases, do not have phenylalanine deaminase, form H2S (some do not), react positively with MR, grow on citrate starvation agar (except S. typhi), do not ferment lactose (except S. arizonae and S. diarizonae), do not form indole, do not have urease and give a negative Voges-Proskauer reaction. The G + C content in DNA is 50-52%. The cultural properties of these bacteria are the same as those of the causative agents of typhus and paratyphoid A and B.

Salmonella resistance

The resistance of Salmonella to some physical and chemical factors is quite high. Heating at a temperature of 70 °C is maintained for 30 minutes. Heat resistance increases when Salmonella is present in foods, especially meat. When cooked for 2.5 hours, meat contaminated with salmonella and placed in cold water becomes sterile in pieces weighing no more than 400.0 g with a piece thickness of 19 cm; and when placed in boiling water, sterility for the same cooking period is achieved only in pieces weighing up to 200.0 g, with a thickness of 5.0-5.5 cm. Salting and smoking meat has a relatively weak effect on salmonella. With a NaCl content of 12-20% in salted and smoked meat, salmonella survive at room temperature for up to 1.5-2 months. Conventional chemical disinfectants kill salmonella in 10-15 minutes.

Salmonella pathogenicity factors

Salmonella has adhesion and colonization factors, invasion factors; they have endotoxin and, finally, they, at least S. typhimurium and some other serotypes, can synthesize two types of exotoxins:

heat-labile and heat-stable enterotoxins of type LT and ST;

Shiga-like cytotoxins.

A feature of toxins is intracellular localization and release after destruction of bacterial cells. Salmonella LT is structurally and functionally similar to the LT of enterotoxigenic E. coli and cholerogens. Its molecular mass is 110 kDa and is stable in the pH range 2.0-10.0. Toxin formation in Salmonella is combined with the presence of two factors of skin permeability:

fast-acting - produced by many strains of salmonella, heat-stable (at 100 ° C it remains for 4 hours), acts for 1-2 hours;

delayed - thermolabile (destroyed at 75 ° C for 30 minutes), causes an effect (thickening of the rabbit's skin) 18-24 hours after administration.

Molecular mechanisms of diarrhea caused by LT and ST Salmonella appear to be. are also associated with dysfunction of the adenylate and guanylate cyclase systems of enterocytes. The cytotoxin produced by Salmonella is thermolabile, its cytotoxic effect is manifested in the inhibition of protein synthesis by enterocytes. It was found that some strains of Salmonella can simultaneously synthesize LT, ST and cytotoxin, while others can synthesize only cytotoxin.

The virulence of Salmonella also depends on the plasmid found in them with mm. 60 MD, its loss significantly reduces the virulence of bacteria. It is assumed that the appearance of epidemic Salmonella clones is associated with their acquisition of virulence plasmids and R-plasmids.

Post-infectious immunity

Post-infectious immunity has not been studied enough. Judging by the fact that mainly children suffer from salmonellosis, post-infectious disease is quite intense, but is apparently type-specific.

Epidemiology of salmonellosis

Of the known salmonellae, only S. typhi and S. paratyphi A cause disease only in humans - typhoid fever and paratyphoid fever A. All other salmonellae are also pathogenic for animals. The primary source of salmonella are animals: cattle, pigs, waterfowl, chickens, synanthropic rodents and a large number of other animals. Animal diseases caused by Salmonella are divided into 3 main groups: primary salmonellosis, secondary salmonellosis and bovine enteritis. Primary salmonellosis (calf paratyphoid, piglet typhus, chicken typhus, chicken dysentery, etc.) are caused by certain pathogens and occur with a characteristic clinical picture. Secondary salmonellosis occurs under conditions when the animal’s body, as a result of some reason (often various diseases), is sharply weakened; they are not associated with specific types of Salmonella in certain animals, but are caused by various serotypes, but most often by S. typhimuriwn.

Enteritis of cattle is characterized by a certain clinical picture and in this respect is similar to primary salmonellosis. However, enteritis in this case is a secondary manifestation, while the primary role is played by various predisposing circumstances. Its causative agents are most often S. enteritidis and S. typhimurium.

The most dangerous sources of foodborne toxic infections are animals suffering from secondary salmonellosis and bovine enteritis. Waterfowl and their eggs, as well as chickens, their eggs and other poultry products play a major role in the epidemiology of salmonellosis. Salmonella can enter the egg directly during its development, but can easily penetrate through an intact shell. Outbreaks of toxic infections are most often associated with the consumption of meat infected with salmonella - up to 70-75%, including up to 30% of meat from forced slaughter. Animals in an agonal state are often subjected to forced slaughter. In weakened animals, salmonella easily penetrates from the intestines into the blood, and through it into the muscles, causing intravital infection of meat. Eggs and poultry products account for more than 10%, milk and dairy products for about 10%, and fish products for about 3-5% of all salmonellosis outbreaks.

Modern epidemiology of salmonellosis is characterized by a constant increase in the incidence of people and animals and an increase in the number of Salmonella serotypes that cause these diseases. From 1984 to 1988 in England, the number of cases of salmonellosis increased 6 times. However, WHO experts believe that the true number of salmonellosis cases remains unknown. In their opinion, no more than 5-10% of infected individuals are detected. One of the main reasons for the increase in the incidence of salmonellosis is the infection of food products during their production as a result of the widespread spread of salmonella in environmental facilities and in processing plants, which receive animals in which salmonellosis occurs in a latent form. One of the main reasons for the widespread circulation of salmonella among animals is the use of feed containing processed animal by-products and very often contaminated with salmonella.

Despite the constant increase in the number of Salmonella serotypes isolated from humans and animals, up to 98% of all cases of salmonellosis are still caused by Salmonella of groups A, B, C, D and E, primarily S. typhimurium and 5. enteritidis (up to 70- 80% of disease cases).

Another important feature of the modern epidemiology of salmonellosis is the establishment of the role of humans as a source of salmonella infection. Infection of a person from a patient or a bacteria carrier is possible not only through food, in which salmonella find good conditions for reproduction, but also through contact and household contact. This method of infection leads to widespread asymptomatic carriage of bacteria.

A large water epidemic of salmonella infection in 1965 in Riverside (USA), caused by S. typhimurium (about 16 thousand people fell ill), showed that infection with salmonella is possible not only through food, but also through water.

Features of the epidemiology of salmonellosis in recent years should also include an increase in the etiological role of S. enteritidis, activation of the food route of transmission of infectious agents with a predominance of poultry and poultry products, an increase in the number of group diseases, including nosocomial ones, an increase in morbidity among children under 14 years of age (more than 60 % of all cases of disease).

Symptoms of salmonellosis

Salmonellosis can occur with a different clinical picture: in the form of food poisoning, salmonellosis diarrhea and a generalized (typhoid) form - it all depends on the size of the infecting dose, the degree of virulence of the pathogens and the immune organism. Massive contamination of a food product with Salmonella causes food toxicoinfection, in which the main symptoms are associated with the entry of the pathogen into the blood in large quantities, its breakdown and release of endotoxin. Salmonella diarrhea is based on colonization of enterocytes by Salmonella. After attaching to the glycocalyx of the small intestine, Salmonella penetrate between the villi and, attaching to the plasma membrane of the enterocytes, colonize it, damage the microvilli, cause desquamation of the enterocytes and moderate inflammation of the mucous membrane. The released enterotoxin causes diarrhea, and the cytotoxin causes cell death. Salmonella multiply on the plasmalemma, but not in enterocytes, but they invade through the epithelium into the underlying tissues of the mucous membrane, they are transported through it in macrophages, enter the lymph and blood, causing bacteremia and generalization of the infectious process.

Salmonella classification

The genus Salmonella includes the following species: Salmonella bongori, Salmonella subterranea, S. enteritica (formerly S. choleraesuis) with six main subspecies: S. salamae, S. arizonae, S. diarizonae, S. houtenae, S. indica, S. enterica which differ in a number of biochemical characteristics.

Serological classification of Salmonella according to White and Kauffmann

Salmonella has O-, H- and K-antigens. 65 different O-antigens have been discovered. They are designated by Arabic numerals from 1 to 67. Based on the O-antigen, Salmonella are divided into 50 serological groups (A-Z, 51-65). Some O-antigens are found in Salmonella of two groups (Ob, 08); antigens 01 and 012 are found in representatives of many serogroups, but representatives of each serogroup have one main O-antigen, common to all, by which they are divided into serogroups. The specificity of O-antigens is determined by the LPS polysaccharide. All Salmonella polysaccharides have a common inner core to which are attached O-specific side chains consisting of a repeating set of oligosaccharides. Differences in the bonds and compositions of these sugars provide the chemical basis for serological specificity. For example, the specificity of the 02 antigen is determined by the sugar paratose, 04 by abequoise, 09 by thyvelose, etc.

In Salmonella there are two types of H-antigens: phase I and phase II. More than 80 variants of phase I H-antigens have been discovered. They are designated by lowercase Latin letters (a-z) and Arabic numerals (Zj-z59). Phase I H-antigens are found only in certain serotypes, in other words, based on H-antigens, serogroups are divided into serotypes. Phase II H-antigens have common components; they are designated by Arabic numerals and are found in different serovars. 9 H-antigens of phase II were detected.

Salmonella K-antigens are presented in different variants: Vi- (S. typhi, S. paratyphi C, S. dublin), M-, 5-antigens. The significance of the Vi antigen is discussed above.

The modern serological classification of Salmonella already includes over 2500 serotypes.

For serological identification of salmonella, diagnostic adsorbed mono- and polyvalent O- and H-sera are produced, containing agglutinins to the O- and H-antigens of those Salmonella serotypes that most often cause diseases in humans and animals.

Most Salmonella (about 98%) are sensitive to Salmonella phage 01. In addition, a phage typing scheme for the most common pathogen of salmonellosis, S. typhimurium, has been developed; it allows the differentiation of more than 120 of its phage types.

Laboratory diagnosis of salmonellosis

The main method for diagnosing salmonella infection is bacteriological. The materials for the study are feces, vomit, blood, gastric lavage, urine, and products that caused poisoning. Features of bacteriological diagnosis of salmonellosis:

the use of enrichment media (selenite, magnesium), especially when studying feces;

to detect salmonella, samples should be taken from the last, more liquid part of the stool (the upper part of the small intestine);

maintain a ratio of 1: 5 (one part of feces to 5 parts of medium);

due to the fact that S. arizonae and S. diarizonae ferment lactose, use not only Endo medium as a differential diagnostic, but also bismuth-sulfitagar, on which Salmonella colonies acquire a black (some greenish) color;

use Rapoport medium for blood culture;

use for preliminary identification of colonies of the 01-salmonella phage, to which up to 98% of salmonella are sensitive;

For the final identification of isolated cultures, polyvalent adsorbed O- and H-sera are first used, and then the corresponding monovalent O- and H-sera are used.

Polyvalent immunofluorescent sera can be used for rapid detection of Salmonella. To detect antibodies in the blood serum of patients and survivors, RPGA is used using polyvalent erythrocyte diagnostics containing polysaccharide antigens of serogroups A, B, C, D and E.

Treatment of salmonellosis

In the case of food poisoning, treatment for salmonellosis consists of gastric lavage and the use of antibacterial drugs and agents. For Salmonella diarrhea - restoration of normal water-salt metabolism, antibiotic therapy.

Specific prevention of salmonellosis

Specific prevention of salmonellosis is not used, although various vaccines from killed and live (mutant) strains of S. typhimurium have been proposed.