Causes and agents of food poisoning

The main causes of food poisoning are the unreasonable consumption of products contaminated with bacteria or containing toxins, as well as failure to comply with food processing standards and personal hygiene rules. If we generalize the great variety of factors that provoke food intoxication or toxic infection, we will get just a few words:

• Dirt.
• Poisons.
• Incorrect storage.

Most often, a person is to blame for the infection in one way or another: either he is unwise about his diet and eats food of dubious origin, or he is a hidden carrier of food infection and infects many people around him. Much less often, the causative agent of toxic infection are animals and insects that are capable of carrying the infection. For example, if a cow is sick with purulent mastitis, her milk will be contaminated.

If milk is not boiled or otherwise processed (pasteurized), the risk of food poisoning from dairy products doubles.

Let's list the typical causes of food poisoning:

1. Homo sapiens, who does not observe the rules of personal hygiene and starts cooking. Sadly, such a banal reason is a factor that provokes more than 60% of all food problems.
2. Meat, fish, milk that have not undergone heat treatment. The raw product is considered potentially dangerous in terms of food poisoning.
3. Water contaminated with bacteria, as well as crustaceans and seafood, which, like a sponge, absorb all the harmful substances of the water element.
4. Pets, insects that come into contact with food or cutlery.
5. Unprocessed, unwashed vegetables, fruits, greens. They are often seeded with bacteria found in the soil.

The following factors also contribute to toxic infections:

• Favorable temperature for microbes. The ideal temperature for bacteria reproduction is considered to be the temperature corresponding to the normal human body temperature, i.e. 36.5-37 degrees. However, microorganisms are capable of dividing in harsher conditions, temperature limits from +10 to 65 degrees are quite suitable for them.
• Moisture is what encourages bacteria to grow.
• The time factor is one of the most important. Any division or reproduction takes time, no bacteria in the world can double instantly. If one or two hours pass between the preparation of food and its consumption, this is quite enough for the reproduction of microorganisms. Food should be stored in the refrigerator or served immediately.

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Food poisoning pathogens

Most often, the disease is provoked by a bacterial cause. The most "famous" of all the huge number of harmful microorganisms are staphylococci, E. coli and salmonella. The second step in the ranking is occupied by protozoa, amoebas, parasites and viruses, much less often food poisoning is caused by toxins (poisons) of plant origin, with the exception of the autumn "mushroom" period. It is necessary to distinguish between pathogenic microorganisms that provoke food infections and the concept of causative agents of food poisoning. Bacteria that are the culprits of toxic infections cannot divide and multiply in the digestive tract. The process of reproduction (insemination) occurs directly on the food product.

Here is a list of the main, frequently detected pathogens:

1. Proteus vulgaris – Proteus, a rod belonging to the large family Enterobacteriaceae. The bacterium is extremely mobile, multiplies on the product at room temperature in the open air, in the human body it secretes intestinal poisons (enterotoxins).
2. Staphylococcus aureus is a golden staphylococcus that secretes a strong toxin in the body (in the intestines). Golden staphylococcus is very common and can be found everywhere. Food products such as milk and meat are especially favorable conditions for its reproduction.
3. Clostridia of various species. Particularly dangerous is the species Clostridium perfringens, which is found in soil (earth), animal and human feces. The toxin secreted by clostridia is aggressive and quickly penetrates the bloodstream, affecting the kidneys, liver, and vascular walls. The disease is characterized by frequent fatal outcomes due to anaerobic sepsis.
4. Clostridium botulinum is a botulinum toxin that causes acute symptoms, a severe course of the disease with a fairly high percentage of fatal outcomes. The pathogen is an anaerobic bacillus, that is, one that reproduces only without access to air (canning, sealed packaging).
5. Bacillus cereus – cereus, a gram-positive microorganism of the genus Bacillus. Symptoms of infection with cereus resemble the acute symptoms of the disease caused by clostridia. The bacterium produces two dangerous toxins that cause severe vomiting and uncontrollable diarrhea.
6. Klebsiella – Klebsiella, a bacterium that can survive for many months in soil and household dust. The microorganism enters the human body through dirty hands, unwashed vegetables, berries, fruits, and through water. Klebsiella belongs to the category of opportunistic microorganisms, since it is normally present in certain quantities in the human intestinal microflora.
7. Enterococcus – enterococci are a subspecies of lactobacilli of the streptococcal genus. Enterococci reproduce in almost any moist, warm environment. This is also a conditionally pathogenic microorganism living in the human body. Mass seeding of food products with Enterococcus can cause food poisoning.

Almost all food poisoning pathogens are extremely tenacious and resistant to temperature effects. The main factor contributing to the transmission of pathogens is insufficiently thorough processing of food products, their improper preparation or improper storage. Susceptibility to all pathogens is very high; according to statistics, 85-90% of people who have eaten contaminated food become ill.

Staphylococcal food poisoning

There are certain types of pathogenic staphylococci that produce a strong enterotoxin when they enter the digestive tract through food. Staphylococcal food poisoning is a variant of infection with one of six serotypes of the bacterium. Serotypes are distributed according to the letters of the alphabet, respectively, A, B, C, D, E, F subtypes are distinguished. The specified types of staphylococcus belong to Staphylococcus aureus, as they form a characteristic golden pigment.

Staphylococcus aureus is very resistant to any conditions and can survive in frozen products for six months. Staphylococcus is not afraid of acidic environments, high temperatures, alkalis. In order to neutralize the infection, a long process of boiling or frying at a temperature of at least 75-80 degrees is needed. The favorite environment for the reproduction of Staphylococcus aureus is milk and all dairy products, it is milk that most often becomes a source of toxic infection caused by staphylococcus bacteria. Microorganisms can multiply at temperatures from 16-18 to 37-40 degrees, for insemination of a dairy product sometimes 4-5 hours are enough. Enterotoxin is produced, as a rule, in products made from unboiled or unpasteurized milk. The source of infection is fresh feta cheese, curd mass, sour cream, cheeses made with rennet. Also dangerous are all sweet confectionery products with a cream layer, especially with custard cream on milk. Sugar, a moist milk environment, starch are favorable conditions for the vital activity of staphylococcus.

Less frequently, staphylococcus inseminates meat and meat products. It affects sick animals with a weakened immune system or multiplies on meat food stored in improper conditions.

The organoleptic properties of dairy, meat or vegetable dishes inoculated with staphylococcus do not change, so the taste and smell of the food are absolutely no different from healthy, uninfected food. The main culprit, due to which staphylococcal food poisoning occurs, is the human factor, that is, the person who prepares, stores, or in any way comes into contact with food. Also, a sick animal can be a source of infection, for example, a cow with mastitis or diseases of the internal organs. In such cases, milk is inoculated, and the meat of the slaughtered animal can be contaminated.

Food poisoning of unknown etiology

Diseases of unknown, unclear etiology are rare in modern clinical practice. However, food poisoning of unknown etiology still occurs, which could be studied more thoroughly if not for the constant seasonal mass infections with already known pathogens. Foodborne diseases with an unclear cause include:

1. Kashin-Beck disease (Urov disease). The disease has a clear territorial localization - the Amur region and the Transbaikal zone. Isolated cases were diagnosed in China, in the central zone of Russia. The disease was first described by Kashin at the end of the 19th century, his data were confirmed decades later, when in the valley of the small Urov River, Dr. Beck treated an entire settlement suffering from degenerative changes in the skeletal system. Most often, Urov disease affects children and adolescents aged 5-6 to 14-16 years. Apparently, during the period of rapid formation of the skeletal system and restructuring of the body, due to a lack of calcium in food, children's spine and limbs are deformed. Also, one of the causes of the disease, according to modern microbiologists, may be an imbalance in the content of trace elements in local water sources (excess silver, magnesium and lack of selenium).
2. Haff disease, Yuks or Sartlan disease or paroxysmal toxic myoglobinuria (ATMM). Judging by the variety of name options, the disease has not yet been fully studied. The disease is also clearly localized by the territorial epidemiological picture and is most often found in the coastal zones of lakes in Western Siberia, the Urals, in some water areas of St. Petersburg, the Baltic countries and in Ukraine. Symptoms of Haff disease are characterized by sudden, paroxysmal muscle pain. The pain is so intense that it leads to temporary immobilization of a person. Attacks can last up to 4-5 days and cause asphyxia due to paralysis of the diaphragm and intercostal muscles. The source of infection is considered to be fish, which in turn becomes toxic due to pollution of the aquatic environment, due to the growth of a poisonous plant - ergot in the area of water bodies, as well as due to contamination of water with toxins of blue-green and brown algae.
3. Sigvatera is a toxic infection that occurs among people living on the coast of the Indian and Pacific Oceans, in the countries of Central America. The toxin is produced by about 300 species of sea and ocean inhabitants that are used as food. People can be poisoned by octopus, marlin, tuna, mackerel. According to one version, fish accumulate the toxin (ichthyosarcotoxin) because they feed on poisonous small organisms. Sigvatera is extremely severe, causing itching similar to an allergic reaction, then persistent numbness of the tongue and lips develops. Vomiting and diarrhea, photosensitivity, rash are possible, but the danger is paralysis of the respiratory system. Mortality is 7-10% of the total number of diseases, and victims recover with difficulty and for a long time.

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Types of food poisoning

Food poisoning in clinical practice is divided into the following types:

1. microbial diseases.
2. food poisoning of non-microbial etiology.
3. food poisoning of unknown etiology.

The table below clearly shows the distribution of types of food poisoning and the main causes that provoke them.

Species, group	Subgroup	The main factor, the reason
Microbial food poisoning	Toxic infections	1. Saprophytes, Citrobacter, Serratia, Klebsiella - intestinal sticks. 2. Cereus, Proteus, Enterococci, Klebsiella perfringens, Vibrio parahaemolyticus
	Types of toxicosis:
	1.Bacteriotoxicosis	Staphylococcus aureus, botulinum bacillus, cereus emetic form
	2. Mycotoxicoses	Fusaria, ergot, microfungi
Food poisoning of non-microbial etiology	Plants that are poisonous by nature	Wild flowers, berries, herbs, mushrooms
	Product components, product parts that are toxic	Milk, roe of some fish species
	Products that have become toxic due to storage conditions	Cherry, apricot and almond pits, potatoes that have been exposed to the light and sun, sprouted potato tubers, raw fresh beans (white), beech nuts. Fish roe stored in improper conditions

Types of toxic infections are important not only for accurate diagnosis and study of the disease, but also for choosing effective therapy, on which the life of the victim often depends (mushroom poisoning, caviar).

Microbial food poisoning

Microbial food poisoning accounts for almost 95% of all toxic infections; these diseases can occur in different forms and are divided into:

1. Food poisoning.
2. Food intoxication (toxicosis).
3. Food contaminated with bacteria is the main source of infection, but humans are considered primarily responsible for the disease.

Microbial food poisoning - toxicoinfections. These are the most common diseases that begin at once and are associated with the consumption of the same dish, product by many people. Food toxicoinfection begins and proceeds very acutely, but also passes quickly. Toxicoinfections are provoked by such pathogens:

• Proteas.
• Cereus.
• Clostridium perfringens rods.
• Vibrio parahaemolyticus.
• Citrobacter.
• Enterobacter.

Toxic infections most often appear in the warm season and are associated with food products that have not undergone proper heat treatment. The main sources of the disease are dairy products, main courses (salads, mashed potatoes), minced meat dishes (meat, fish). These diseases rarely last more than 5 days and have a favorable prognosis. An exception is toxic infection caused by the bacterium Clostridium perfringens, which can cause necrotic enteritis.

Microbial food poisoning - toxicosis. These are diseases that occur due to the consumption of food containing bacterial toxins. The causative agents of food toxicosis can be:

1. Staphylococcus aureus.
2. Botulinum toxin stick.
3. Fungi – Fusarium, Penicillium, Aspergillus (mycotoxicoses).

Bacterial food poisoning

Food poisoning contaminated with bacteria is called foodborne toxic infections (FTI). Most often, the disease is caused by toxins produced by the following pathogens:

1. Staphylococcus aureus, a golden staph bacteria, produces a toxin that affects the human digestive tract. Staphylococcus aureus is very resistant to environmental changes and can survive even at low temperatures. Food is an ideal environment for Staphylococcus aureus, especially if there is the right level of humidity and warmth. Any cooked dish that is not eaten immediately but left on the table is a potentially dangerous source of staphylococcus infection. This is especially true for dairy products, pastries with custard, and dishes seasoned with mayonnaise (salads).
2. Cereus - Bacillus cereus "loves" all rice dishes, and can also be found in dry rice. If pilaf or rice porridge is on the table for 2-3 hours, the bacteria may well begin to produce a toxin. Cereus is very resistant to high temperatures, even prolonged boiling, including repeated boiling, does not always kill Bacillus cereus.
3. The most dangerous clostridia are Clostridium perfringens, which, according to statistics, in 2% of cases ends in intestinal wall necrosis. The source of infection can be meat dishes that have not undergone proper heat treatment, dishes made from beans, poultry. In a mild form, infection with clostridia passes quite quickly.

Bacterial food poisoning is the most frequently diagnosed disease, it is fairly well studied by the medical world, but continues to affect a large number of people. Most likely, this is due to insufficient public awareness of the dangers of toxic infections and failure to comply with basic sanitary standards and personal hygiene rules.

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Non-microbial food poisoning

Food poisoning of non-microbial etiology does not account for more than 10% of the total number of food-related toxic infections.

Non-microbial food poisoning is classified as follows:

1. Poisoning by plants, plant parts (seeds), mushrooms, that is, food substances that may be poisonous by their nature.
2. Poisoning associated with the consumption of raw fresh beans and certain types of toxic fish.
3. Poisoning by products that are not poisonous in principle, but can become so due to changes in storage conditions and under the influence of physiological factors. This applies to potatoes (solanine), fish going to spawn.
4. Poisoning by toxic substances that are part of kitchen utensils (copper, zinc, lead). This applies to pots, pans, plastic utensils.

Non-microbial food poisoning with mushrooms is related to the season; in winter, it is almost never encountered. There is a well-known list of poisonous mushrooms, which includes fly agarics, morels, death cap, false honey fungus and other species. The most dangerous is the death cap, it causes acute poisoning, which in 90% of cases ends in death. You can also get poisoned by the pits of the fruit if you eat them in unlimited quantities. The poison - amygdalin in the human body is transformed into hydrocyanic acid. Raw beans are dangerous because they contain a toxin that can be neutralized by regular heat treatment. Certain types of fish - puffer fish, marinka, barbel during spawning produce a toxin that is dangerous to humans, contained in caviar and milt. Zinc or copper poisoning can occur due to violation of the rules for using kitchen utensils.