The influence of xenobiotics on the human body. What are xenobiotics and how are they destroyed? Properties of xenobiotics coming from the external environment into the human body

Many of us have been familiar with the series since childhood about the invincible warrior, Princess Xena (Xena), who fights the forces of evil. Did you know that “Xena” translated from Greek means “stranger”?

In addition to the militant princess, a family of harmful substances foreign to the body bears the same name.

Meet xenobiotics!

Xenobiotics are antibiotics, pesticides, herbicides, synthetic dyes, detergents, hormones and other chemical compounds. They are found in soil, water, products, and air. These substances, foreign to our body, entering the body, undermine the immune system and become the cause of and. Unfortunately, it is simply unrealistic today to completely isolate yourself from their harmful influence.

Xenobiotics cause disruption of the functioning of many organs, and, as a result, cause diseases of the digestive, respiratory, cardiovascular system, and kidneys. With prolonged exposure to humans, xenobiotics become the cause of malignant tumors.

Mother Nature has provided protection mechanisms against strangers. They are destroyed by cells of the immune system, liver, and there are even cellular barriers to various toxic substances.

And humanity, which invented these xenobiotics, also came up with intestinal sorbents (Enterosgel). Thanks to enterosorbents, “harmful” molecules are absorbed and ensure proper functioning of the liver, protecting cells from harmful factors.

In order for the defense to be strong, the body needs helpers - nutrients. Who could it be?

Vitamins

Vitamins protect immune cells from damage.

The main sources of vitamins: vegetables, fruits, cereals, seaweed, green tea.

Minerals

Microelements are responsible for immunity: selenium, magnesium and zinc.

These minerals are found in cereals, legumes, seafood, liver, and eggs.

Cholesterol and phospholipids

These substances are the “building blocks” for cell membranes, in particular liver cells. A sufficient supply of these phospholipids with food ensures the “resistance” of liver cells to “strangers”. Fatty acids, choline, and “good” cholesterol are found in sea fish, nuts, yolks, and flax seeds.

Squirrels

Liver function is directly related to what we eat daily. With insufficient consumption of protein foods, liver activity decreases.

Where does the body get the necessary proteins?

In nuts, greens, legumes, eggs, poultry, river and sea fish, low-fat cheese, milk.

Cellulose

When starting the fight against xenobiotics, we must not forget about the benefits of dietary fiber. They, like Enterosgel, retain a large number of toxins and carcinogens on their surface.

Fruit and vegetable purees, marmalade, oat and wheat bran, and seaweed are rich in dietary fiber (fiber).

Phytoncides

Everyone knows the benefits of phytoncides. They are always talked about a lot during the fight against influenza and other viral infections. The most phytoncides are in onions and garlic. Rich in phytoncides:

Carrots, horseradish, tomato, bell pepper, Antonovka apples, .

Berries: blueberries, blackberries, dogwood, viburnum;

Ginger, turmeric.

Harmful foods: list

A considerable part of xenobiotics enters the body “thanks to” our culinary preferences. In order not to expose ourselves to unnecessary risks, let's give up junk food!

So, on the black list:

sausages, sausages, smoked meats;

margarine, mayonnaise, vinegar;

confectionery and sweet carbonated drinks;

Does this mean that they should be excluded from the diet? Your health is yours, so “think for yourself, decide for yourself!”

Unfortunately, it is not always possible to avoid products from the “hit” list - it is for such cases that enterosorbent No. 1 exists - Enterosgel! This drug, created by order of the USSR Ministry of Defense, helps effectively and healthily fight poisoning, allergies, harmful food additives and even.

Abstract on the topic:

ALIEN SUBSTANCES – XENOBIOTIICS

1. The concept of “xenobiotics”, their classification

Foreign substances that enter the human body with food and are highly toxic are called xenobiotics, or pollutants.

“The toxicity of substances refers to their ability to harm a living organism. Any chemical compound can be toxic. According to toxicologists, we should talk about the harmlessness of chemicals in the proposed method of their use. The decisive role is played by: dose (the amount of a substance entering the body per day); duration of consumption; admission mode; routes of entry of chemicals into the human body.”

When assessing the safety of food products, the basic regulations are the maximum permissible concentration (hereinafter MAC), permissible daily dose (hereinafter ADI), permissible daily intake (hereinafter ADI) of substances contained in food.

The maximum permissible concentration of a xenobiotic in food is measured in milligrams per kilogram of product (mg/kg) and indicates that its higher concentration is dangerous for the human body.

ADI of a xenobiotic is the maximum dose (in mg per 1 kg of human weight) of a xenobiotic, the daily oral intake of which is harmless throughout life, i.e. does not have an adverse effect on the life activity and health of present and future generations.

ADI of a xenobiotic is the maximum amount of xenobiotic that can be consumed for a particular person per day (in mg per day). It is determined by multiplying the permissible daily dose by the person’s weight in kilograms. Therefore, the xenobiotic ADI is individual for each individual, and it is obvious that for children this indicator is significantly lower than for adults.

The most common classification of contaminants in food raw materials and food products in modern science comes down to the following groups:

1) chemical elements (mercury, lead, cadmium, etc.);

2) radionuclides;

3) pesticides;

4) nitrates, nitrites and nitroso compounds;

5) substances used in animal husbandry;

6) polycyclic aromatic and chlorine-containing hydrocarbons;

7) dioxins and dioxin-like substances;

8) metabolites of microorganisms.

The main sources of contamination of food raw materials and food products.

Atmospheric air, soil, water contaminated with human waste.

Contamination of plant and livestock raw materials with pesticides and substances that are products of their biochemical transformations.

Violation of technological and sanitary-hygienic rules for the use of fertilizers and irrigation water in agriculture.

Violation of the rules for the use of feed additives, growth stimulants, and medicines in livestock and poultry farming.

Technological process of production.

Use of unauthorized food, biologically active and technological additives.

Use of approved food, biologically active and technological additives, but in increased doses.

Introduction of new poorly tested technologies based on chemical or microbiological synthesis.

Formation of toxic compounds in food products during cooking, frying, irradiation, canning, etc.

Failure to comply with sanitary and hygienic production rules.

Food equipment, utensils, utensils, containers, packaging containing harmful chemicals and elements.

Failure to comply with technological and sanitary-hygienic rules for the storage and transportation of food raw materials and food products.

2. Pollution with chemical elements

The chemical elements discussed below are widespread in nature; they can enter food products, for example, from soil, atmospheric air, ground and surface water, agricultural raw materials, and through food into the human body. They accumulate in plant and animal raw materials, which determines their high content in food products and food raw materials.

Most macro- and microelements are vital for humans, while for some a specific role in the body has been established, for others this role has yet to be determined.

It should be noted that chemical elements exhibit biochemical and physiological effects only in certain doses. In large quantities they have a toxic effect on the body. For example, the high toxic properties of arsenic are known, but in small quantities it stimulates hematopoietic processes.

Thus, most chemical elements in strictly defined quantities are necessary for the normal functioning of the human body, but their excess intake causes poisoning.

According to the decision of the joint commission of the Food and Agriculture Organization of the United Nations (hereinafter referred to as FAO) and the World Health Organization (hereinafter referred to as WHO) on the Food Code, the components whose content is controlled in international food trade include eight chemical elements: mercury, cadmium, lead, arsenic , copper, zinc, iron, strontium. The list of these elements is currently being expanded. In Russia, medical and biological requirements define safety criteria for the following chemical elements: mercury, cadmium, lead, arsenic, copper, zinc, iron, tin.

3. Toxicological and hygienic characteristics of chemical elements

Lead. One of the most common and dangerous toxicants. It is found in the earth's crust in small quantities. At the same time, 4.5 × 105 tons of lead per year enter the atmosphere alone in a processed and finely dispersed state.

The lead content in tap water is expected to be no higher than 0.03 mg/kg. It should be noted the active accumulation of lead in plants and meat of farm animals near industrial centers and major highways. An adult receives 0.1-0.5 mg of lead daily from food, and about 0.02 mg from water. Its total content in the body is 120 mg. From the blood, lead enters soft tissues and bones. 90% of incoming lead is excreted from the body with feces, the rest with urine and other biological fluids. The biological half-life of lead from soft tissues and organs is about 20 days, from bones – up to 20 years.

The main targets of lead exposure are the hematopoietic, nervous, digestive systems and kidneys. A negative effect on the sexual function of the body was noted.

Measures to prevent lead contamination of food products should include state and departmental control over industrial emissions of lead into the atmosphere, water bodies, and soil. It is necessary to reduce or completely eliminate the use of lead compounds in gasoline, stabilizers, polyvinyl chloride products, dyes, and packaging materials. Of no small importance is hygienic control over the use of tinned food utensils, as well as glazed ceramic utensils, the poor manufacturing of which leads to contamination of food products with lead.

Cadmium. It is not found in nature in its pure form. The earth's crust contains about 0.05 mg/kg of cadmium, sea water - 0.3 μg/kg.

Cadmium is widely used in the production of plastics and semiconductors. In some countries, cadmium salts are used in veterinary medicine. Phosphate fertilizers and manure also contain cadmium.

All this determines the main ways of pollution of the environment, and, consequently, of food raw materials and food products. In normal geochemical regions with a relatively clean ecology, the cadmium content in plant products is, mcg/kg: grains - 28-95; peas – 15-19; beans – 5-12; potatoes – 12-50; cabbage – 2-26; tomatoes – 10-30; salad – 17-23; fruits – 9-42; vegetable oil – 10-50; sugar – 5-31; mushrooms – 100-500. In products of animal origin, on average, mcg/kg: milk – 2.4; cottage cheese – 6; eggs – 23-250.

It has been established that approximately 80% of cadmium enters the human body through food, 20% through the lungs from the atmosphere and through smoking.

With the diet, an adult receives up to 150 or more micrograms of cadmium per 1 kg of body weight per day. One cigarette contains 1.5-2.0 mcg of cadmium, so its level in the blood and kidneys of smokers is 1.5-2.0 times higher than in non-smokers.

92-94% of cadmium that enters the body with food is excreted in urine, feces and bile. The rest is found in organs and tissues in ionic form or in complex with protein molecules. In the form of this compound, cadmium is not toxic, therefore the synthesis of such molecules is the body’s protective reaction when receiving small amounts of cadmium. A healthy human body contains about 50 mg of cadmium. Cadmium, like lead, is not an essential element for mammals.

When cadmium enters the body in large doses, it exhibits strong toxic properties. The main target of biological action is the kidneys. The ability of cadmium in large doses to disrupt the metabolism of iron and calcium is known. All this leads to the emergence of a wide range of diseases: hypertension, anemia, decreased immunity, etc. Teratogenic, mutagenic and carcinogenic effects of cadmium have been noted.

The ADI of cadmium is 70 µg/day, the ADI is 1 µg/kg. The maximum permissible concentration of cadmium in drinking water is 0.01 mg/l. The concentration of cadmium in wastewater entering water bodies should not exceed 0.1 mg/l. Taking into account the particle board of cadmium, its content in 1 kg of daily food intake should not exceed 30-35 mcg.

Proper nutrition is important in the prevention of cadmium intoxication: the predominance of plant proteins in the diet, a rich content of sulfur-containing amino acids, ascorbic acid, iron, zinc, copper, selenium, and calcium. Prophylactic UV irradiation is necessary. It is advisable to exclude foods rich in cadmium from the diet. Milk proteins contribute to the accumulation of cadmium in the body and the manifestation of its toxic properties.

Arsenic. Contained in all objects of the biosphere: sea water - about 5 mg/kg, the earth's crust - 2 mg/kg, fish and crustaceans - in the largest quantities. The background level of arsenic in food from normal geochemical regions averages 0.5-1 mg/kg. A high concentration of arsenic, as well as other chemical elements, is observed in the liver and food aquatic organisms, in particular marine ones. About 1.8 mg of arsenic is found in the human body.

FAO/WHO has established an ADI for arsenic of 0.05 mg/kg body weight, which is about 3 mg/day for an adult.

Arsenic, depending on the dose, can cause acute and chronic poisoning. Chronic intoxication occurs with long-term consumption of drinking water with 0.3-2.2 mg of arsenic per 1 liter of water. A single dose of arsenic of 30 mg is lethal to humans. Specific symptoms of intoxication include thickening of the stratum corneum of the skin of the palms and soles. Inorganic arsenic compounds are more toxic than organic ones. After mercury, arsenic is the second most toxic element found in food. Arsenic compounds are well absorbed in the gastrointestinal tract. 90% of arsenic entering the body is excreted in the urine. The biological maximum concentration limit for arsenic in urine is 1 mg/l, and a concentration of 2-4 mg/l indicates intoxication. In the body, it accumulates in hair, nails, and skin, which is taken into account during biological monitoring. The necessity of arsenic for the vital functions of the human body has not been proven, with the exception of its stimulating effect on the process of hematopoiesis.

Arsenic contamination of food products is due to its use in agriculture. Arsenic is used in the production of semiconductors, glass, and dyes. Uncontrolled use of arsenic and its compounds leads to its accumulation in food raw materials and food products, which creates a risk of possible intoxication and determines ways of prevention.

Mercury. One of the most dangerous and highly toxic elements, which has the ability to accumulate in the body of plants, animals and humans. Due to their physicochemical properties - solubility, volatility - mercury and its compounds are widely distributed in nature. In the earth's crust its content is 0.5 mg/kg, in sea water - about 0.03 μg/kg. In the body of an adult it is about 13 mg, but its necessity for vital processes has not been proven.

Contamination of food with mercury can occur as a result of:

the natural process of evaporation from the earth’s crust in the amount of 25-125 thousand tons annually;

the use of mercury in the national economy - the production of chlorine and alkali, mirrors, the electrical industry, medicine and dentistry, agriculture and veterinary medicine;

the formation by some groups of microorganisms of methylmercury, dimethylmercury, and other highly toxic compounds entering the food chain.

Fish meat has the highest concentration of mercury and its compounds, which are actively accumulated in the body from water and feed containing other aquatic organisms rich in mercury. In the meat of predatory freshwater fish, the level of mercury is 107-509 µg/kg, non-predatory - 79-200 µg/kg, ocean - 300-600 µg/kg. The fish body is capable of synthesizing methylmercury, which accumulates in the liver.

When cooking fish and meat, the concentration of mercury in them decreases, but when mushrooms are processed in a similar way, it remains unchanged.

Inorganic mercury compounds are excreted mainly in urine, organic ones - in bile and feces. The half-life of inorganic compounds from the body is 40 days, and that of organic compounds is 76.

Zinc and especially selenium have a protective effect when exposed to mercury on the human body. The toxicity of inorganic mercury compounds is reduced by ascorbic acid and copper with their increased intake into the body, while the toxicity of organic compounds is reduced by proteins, cystine, and tocopherols.

A safe level of mercury in the blood is considered to be 50-100 mcg/l, hair – 30-40 mcg/g, urine – 5-10 mcg/day. A person receives 0.045-0.060 mg of mercury in their daily diet, which approximately corresponds to the FAO/WHO recommended ADI of 0.05 mg. The maximum permissible concentration of mercury in tap water used for cooking is 0.005 mg/l, the international standard is 0.01 mg/l (WHO, 1974).

Copper, unlike mercury and arsenic, takes an active part in life processes, being part of a number of enzyme systems. The daily requirement is 4-5 mg. Copper deficiency leads to anemia, growth failure, a number of other diseases, and in some cases, death.

However, with prolonged exposure to high doses of copper, a “breakdown” of adaptation mechanisms occurs, which turns into intoxication and a specific disease. In this regard, the problem of protecting the environment and food products from contamination with copper and its compounds is urgent. The main danger comes from industrial emissions, overdose of insecticides, other toxic copper salts, consumption of drinks and food products that come into contact with copper equipment parts or copper containers during the production process.

Zinc. Contained in the earth's crust in the amount of 65 mg/kg, sea water - 9-21 mcg/kg, in the adult human body - 1.4-2.3 g/kg.

Zinc is part of about 80 enzymes, thereby participating in numerous metabolic reactions. Typical symptoms of zinc deficiency are growth retardation in children, sexual infantilism in adolescents, impaired taste and smell, etc.

The daily requirement for zinc for an adult is 15 mg. Zinc contained in plant foods is less available to the body. Zinc from animal products is absorbed by 40%. The zinc content in food products is, mg/kg: meat - 20-40, fish products - 15-30, oysters - 60-1000, eggs - 15-20, fruits and vegetables - 5, potatoes, carrots - about 10, nuts, grains – 25-30, premium flour – 5-8; milk – 2-6 mg/l. In the daily diet of an adult, the zinc content is 13-25 mg. Zinc and its compounds are low toxic. The zinc content in water at a concentration of 40 mg/l is harmless to humans.

At the same time, cases of intoxication are possible due to violation of the use of pesticides, careless therapeutic use of zinc preparations. Signs of intoxication are nausea, vomiting, abdominal pain, diarrhea. It has been noted that zinc in the presence of accompanying arsenic, cadmium, manganese, and lead in the air at zinc enterprises causes “metallurgical” fever in workers.

There are known cases of poisoning from food or drinks stored in galvanized iron containers. In this regard, preparing and storing food in galvanized containers is prohibited. The maximum permissible concentration of zinc in drinking water is 5 mg/l, for fishery reservoirs – 0.01 mg/l.

Tin. The necessity of tin for the human body has not been proven. At the same time, there is about 17 mg of tin in the adult human body, which indicates the possibility of its participation in metabolic processes.

The amount of tin in the earth's crust is relatively small. When tin is consumed with food, about 1% is absorbed. Tin is excreted from the body in urine and bile.

Inorganic tin compounds are low toxic, while organic tin compounds are more toxic. The main source of contamination of food products with tin are cans, flasks, iron and copper kitchen boilers, other containers and equipment that are manufactured using tinning and galvanization. The activity of the transition of tin into a food product increases at storage temperatures above 20° C and at a high content of organic acids, nitrates and oxidizing agents in the product, which increase the solubility of tin.

The danger of tin poisoning increases with the constant presence of its companion - lead. It is possible that tin interacts with certain food substances and the formation of more toxic organic compounds. An increased concentration of tin in products gives them an unpleasant metallic taste and changes color. There is evidence that the toxic dose of tin for a single dose is 5-7 mg/kg body weight. Tin poisoning can cause signs of acute gastritis (nausea, vomiting, etc.) and negatively affects the activity of digestive enzymes.

An effective measure to prevent food contamination with tin is to coat the inner surface of containers and equipment with a durable, hygienically safe varnish or polymer material, observe the shelf life of canned food, especially baby food, and use glass containers for some canned food.

Iron. It ranks fourth among the most common elements in the earth's crust (5% of the earth's crust by mass).

This element is necessary for the life of both plant and animal organisms. In plants, iron deficiency manifests itself in yellowing leaves and is called chlorosis; in humans it causes iron deficiency anemia, since iron is involved in the formation of hemoglobin. Iron performs a number of other vital functions: oxygen transport, formation of red blood cells, etc.

The adult human body contains about 4.5 g of iron. The iron content in food products ranges from 0.07-4 mg per 100 g. The main sources of iron in the diet are liver, kidneys, and legumes. An adult's need for iron is about 14 mg/day; in women during pregnancy and lactation it increases.

Iron from meat products is absorbed by the body by 30%, from plants by 10%.

Despite the active participation of iron in metabolism, this element can have a toxic effect when entering the body in large quantities. Thus, a state of shock was observed in children after accidentally taking 0.5 g of iron or 2.5 g of ferrous sulfate. The widespread industrial use of iron and its distribution in the environment increases the likelihood of chronic intoxication. Contamination of food products with iron can occur through raw materials, through contact with metal equipment and containers, which determines appropriate preventive measures.

6. Polycyclic aromatic and chlorinated hydrocarbons, dioxins and dioxin-like compounds

Polycyclic aromatic hydrocarbons (hereinafter referred to as PAHs) are formed during the combustion of organic substances (gasoline, other types of fuel, tobacco), including during smoking and burning of food products. They are contained in the air (dust, smoke), penetrate into the soil, water, and from there into plants and animals. PAHs are stable compounds and therefore have the ability to accumulate.

In terms of their effect on the human body, PAHs are carcinogens, because they have a depression in the structure of the molecule, characteristic of many carcinogenic substances (Fig. 1).

Fig.1. Benzopyrene

PAHs enter the human body through the respiratory, digestive system, and skin.

The entry of PAHs into the body can be reduced by: preventing food from burning; minimizing the processing of food raw materials and food products with smoke; growing food plants away from industrial areas; Carrying out thorough washing of food raw materials and food products. In addition, smokers and passive smokers are at great risk of getting PAHs into their bodies.

They are volatile, soluble in water, and lipophilic, so they are found everywhere and are included in food chains.

When chlorine-containing hydrocarbons enter the human body, they destroy the liver and damage the nervous system.

Dioxins and dioxin-like compounds. Dioxins - polychlorinated dibenzodioxins (hereinafter PCDD) include a large group of aromatic tricyclic compounds containing from 1 to 8 chlorine atoms. In addition, there are two groups of related chemical compounds - polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs), which are present in the environment, food and feed along with dioxins.

Currently, 75 PCDDs, 135 PCDFs and more than 80 PCBs have been isolated. They are highly toxic compounds with mutagenic, carcinogenic and teratogenic properties.

The sources of dioxins and dioxin-like compounds entering the environment, their circulation, routes of entry into the human body, and the impact on it are presented schematically in Figure 2.

7. Metabolites of microorganisms

Staphylococcal toxins. Staphylococcal intoxication is the most typical food bacterial intoxication. “They are registered in almost all countries of the world and account for more than 30% of all acute bacterial poisonings with an identified pathogen.” Food poisoning is caused mainly by toxins from Staphylococcus aureus.

Fig.2. Sources of dioxins and dioxin-like compounds entering the environment, their circulation, routes of entry and effects on the human body

The main factors influencing the development of Staphylococcus aureus bacteria are temperature, the presence of acids, salts, sugars, some other chemicals, as well as other bacteria.

Staphylococcus aureus bacteria can grow at temperatures from 10 to 45° C. The optimal temperature is 35-37° C. Typically, staphylococcal cells die at 70-80° C, but some species tolerate heating to 100° C for 30 minutes. The toxin released by staphylococcus bacteria is resistant to high temperatures; boiling for two hours is required to completely destroy it.

Most strains of Staphylococcus aureus develop at pH values from 4.5 to 9.3 (optimal values are 7.0-7.5). Staphylococci are sensitive to the presence of certain types of acids in the environment. Acetic, citric, lactic, tartaric and hydrochloric acids are destructive to staphylococci.

It was found that a content of 15-20% sodium chloride in the broth had an inhibitory effect on staphylococcus, and a concentration of 20-25% had a bactericidal effect on it. A sucrose concentration of 50-60% inhibits bacterial growth, and a concentration of 60-70% has a bactericidal effect.

Staphylococcus is activated by chlorine, iodine, various antibiotics and chemicals such as bromine, o-polyphenol and hexachlorobenzene. However, these compounds are not suitable for food processing. Suppression of the growth of Staphylococcus aureus was observed in the presence of a mixture of lactic acid and intestinal bacteria.

Staphylococcal food poisoning outbreaks are typically caused by animal products such as meat, fish and poultry.

They can get into milk from the udder of cows with mastitis. Other sources include the skin of animals and people involved in milk processing.

Fresh fish and poultry are usually free of staphylococci, but may become contaminated during processing, for example during slaughter or subsequent processing. Vacuum packaging inhibits the growth of staphylococcal bacteria in meat products.

Symptoms of staphylococcal intoxication in humans can be observed 2-4 hours after consuming a contaminated food product. However, initial signs may appear after 0.5 or 7 hours. First, salivation is observed, then nausea, vomiting, and diarrhea.

Body temperature rises. 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. The extent of these signs and symptoms, as well as the severity of the disease, are determined mainly by the amount of toxin ingested and the sensitivity of the affected person. Recovery often occurs within 24 hours, but may take several days.

Deaths due to staphylococcal food poisoning are rare.

When the first signs of poisoning appear, you should immediately consult a doctor. First aid consists of gastric lavage, intestinal cleansing, and taking activated charcoal.

To prevent poisoning, it is necessary: do not allow persons suffering from pustular skin diseases or acute catarrhal symptoms of the upper respiratory tract to work with food products; ensure compliance with heat treatment regimes for products that guarantee the death of staphylococcal toxin, as well as create conditions for storing products in refrigerators at a temperature of 2-4 ° C.

Botulinum toxin is considered the most potent poison in the world and is part of the arsenal of biological weapons.

Food poisoning that occurs from eating food containing the toxin from the bacteria Clostridium botulinum is called botulism. This is a serious illness, often fatal.

Clostridium botulinum is a strictly anaerobic bacterium. The microorganism forms heat-resistant endospores.

Spores of various types of Clostridium botulinum are widespread in nature and are regularly isolated from soil in various parts of the world and less often from water, the intestines of fish and other animals.

Clostridium botulinum types A and B multiply in the temperature range from 10 to 50 ° C. Type E can multiply and produce toxin at 3.3 ° C. Complete destruction of Clostridium botulinum spores is achieved at 100 ° C after 5-6 hours, at 105 ° C - after 2 hours, at 120° C – after 10 minutes.

The development of botulobacteria and their toxin formation is retarded by table salt, and at a salt concentration of 6-10% their growth stops.

Clostridium botulinum A and B grow in foods at a pH of 4.6 or lower. Stability in acidic environments is reduced if sodium chloride or other inhibitory agents are present. Clostridium botulinum type E is more sensitive to acids than other types of microorganisms.

It has been found that chlorine can inactivate Clostridium botulinum spores. Clostridium botulinum spores are inactivated by irradiation.

Symptoms of botulism manifest themselves mainly in 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, as a rule, does not experience any particular pain, other than a headache, and remains fully conscious, although his face may lose expressiveness due to paralysis of the facial muscles. The duration of the incubation period is on average 12-36 hours, but can range from 2 hours to 14 days.

Prevention of botulism includes rapid processing of raw materials and timely removal of entrails (especially in fish); widespread use of cooling and freezing of raw materials and food products; compliance with sterilization regimes for canned food; prohibition of the sale of canned goods with signs of bombing or an increased level of defects (more than 2%) - flapping ends of cans, deformations of the body, smudges, etc. - without additional laboratory analysis; sanitary propaganda among the population about the dangers of home canning, especially hermetically sealed canned mushrooms, meat and fish. First aid is similar to that for staphylococcal poisoning.

Mycotoxins. A special and rather dangerous group of toxins of microbiological origin for the human body are mycotoxins. These are toxic metabolites of mold fungi. There are 250 known species of microscopic fungi that produce about 500 toxic metabolites. For example: ergot toxins, which cause “Antonov fire” and “evil writhing”, fusarium toxins, which cause indigestion, coordination of movements, paralysis and death in humans and animals.

Peanuts, corn, grains, legumes, cotton seeds, nuts, some fruits, vegetables, spices, feed, juices, purees, compotes, and jams can be contaminated to a greater extent with mycotoxins. Products contaminated with mycotoxins cause a type of food intoxication called mycotoxicosis.

Prevention of mycotoxicosis includes: regular sanitary, veterinary, agrochemical control; careful sorting of food raw materials and food products before use; the use of chemical methods for destroying mold fungi, which, however, are most often ineffective and expensive; as well as grain grinding and heat treatment of products.

Pathways for food contamination with mycotoxins are schematically presented in Figure 3.

8. Metabolism of foreign compounds in the human body

All foreign compounds entering the human or animal body are distributed in various tissues, accumulate, undergo metabolism and are excreted. These processes require separate consideration.

First, foreign compounds enter the aquatic environment of the body. After all, the human body consists mainly of water, which is distributed as follows:

Fig.3. Ways of food contamination with mycotoxins.

(V.A. Tutelyan, L.V. Kravchenko)

The blood volume of an adult is about 3 liters;

the volume of extracellular fluid washing the internal organs reaches 15 liters;

including the amount of water inside the cells, the total fluid volume is approximately 42 liters.

Drugs and toxic compounds are distributed differently among these constituents. Some remain in the blood, others enter the intercellular spaces or inside the cells. It should be noted that many drugs and toxic compounds are weak acids or bases, which can greatly affect their distribution among cell membranes; they will not penetrate the membranes.

Some xenobiotics can be sequestered in the blood by binding to proteins. Isolating these compounds using blood proteins can limit their effect on cells.

The transformations of xenobiotics in the human body represent a mechanism for maintaining the constancy of the composition of the internal environment of the body during exposure to foreign compounds. It is customary to distinguish two phases of metabolism.

The first phase includes reactions of hydrolysis, reduction and oxidation of the substrate. They usually lead to the introduction or formation of a functional group such as - OH, -NH2, - SH, - COOH, which slightly increases the hydrophilicity of the original compound.

These reactions occur with the active participation of enzymes of the cytochrome system, which carry out the oxidative and reductive metabolism of steroids, fatty acids, retinoids, bile acids, biogenic amines, leukotrienes, as well as exogenous compounds, including drugs, environmental pollutants, and chemical carcinogens. Moreover, the entry of a foreign substance into the body enhances the release of enzymes necessary for metabolism.

The second phase of xenobiotic metabolism includes reactions of glucuronidation, sulfation, acetylation, methylation, conjugation with glutathione, amino acids such as glycine, taurine, glutamic acid. Basically, the reactions of the second phase lead to a significant increase in the hydrophilicity of the xenobiotic, which facilitates their removal from the body. Second-phase reactions usually occur much faster than first-phase reactions, so the rate of metabolism of a xenobiotic is largely dependent on the rate at which the first-phase reaction occurs.

Various biochemical reactions of xenobiotic metabolism take place in the liver, kidneys, lungs, intestines, bladder, and other organs, which often leads to diseases of these organs: cirrhosis and liver cancer, bladder cancer, etc. For example: many enzymatic processes of xenobiotic breakdown take place in the liver, and the elimination of low-molecular metabolic products occurs in the kidneys. The metabolism of ethyl alcohol causes cirrhosis of the liver, and mercury, lead, zinc, and cadmium cause kidney necrosis.

ξενος ) - chemical substances alien to living organisms, naturally not included in the biotic cycle, and, as a rule, directly or indirectly generated by human economic activity. These include: pesticides, mineral fertilizers, detergents (detergents), radionuclides, synthetic dyes, polyaromatic hydrocarbons, etc. Once in the natural environment, they can cause allergic reactions, death of organisms, change hereditary characteristics, reduce immunity, and disrupt metabolism , disrupt the course of processes in natural ecosystems up to the level of the biosphere as a whole. The study of xenobiotic transformations through detoxification and degradation in living organisms and in the external environment is important for organizing sanitary and hygienic measures for nature conservation.

Action of xenobiotics

Xenobiotics are any substances foreign to the body (pesticides, toxins, other pollutants) that can cause disruption of biological processes, not necessarily poisons or toxins. However, in most cases, xenobiotics, when they enter living organisms, can cause various direct undesirable effects, or, due to biotransformation, form toxic metabolites:

toxic or allergic reactions
changes in heredity
decreased immunity
specific diseases (minamata disease, itai-itai, cancer)
distortion of metabolism, disruption of the natural course of natural processes in ecosystems, up to the level of the biosphere as a whole.

Examples of xenobiotics

free metals (cadmium, lead, and others)
freons
petroleum products
plastics, this especially applies to plastic packaging (plastic bags, plastic PET bottles, etc.)
polycyclic and halogenated aromatic hydrocarbons

Some substances classified as xenobiotics can be found in nature, but in extremely low concentrations. Thus, dioxins can be synthesized during forest fires. Many substances, such as xylene, styrene, toluene, acetone, benzene, gasoline vapor or hydrogen chloride, can be classified as xenobiotics if found in the environment at unnaturally high concentrations associated with industrial production.

Biotransformation

List of references

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