Everyone knows that food is a source of energy. However, apart from the necessary materials it may contain different chemical structure of the compound, not only have no nutritional value, but also dangerous to the human body - are harmful and toxic substances.
It must be remembered that human activity has steadily lead to contamination of their environment, from which we get the food, hence the need to understand the diversity of food contaminants and to try to prevent their release into the environment. Harmful food substances can be conventionally divided into two groups. First group - this is actually the natural components of food (specific to a certain type of product of animal or vegetable origin), which in normal or excessive use can cause adverse reactions. She is represented by a large list of biologically active and toxic elements, which in turn are divided into groups that differ in structure and mechanism of action. These include: antivitamin, alkaloids, substances that inhibit the assimilation of minerals, alcohol, cyanogenic glycosides, etc. These are substances on the harmful effects are known, usually in advance (for example, that you can not eat green potatoes, as it contains solanine). second group is represented by agents, not peculiar foods that fall into the food from the environment. As a rule, are chemicals that are made in food specifically to technological effect, or contaminants of food chemical or biological nature. Food contaminants that enter from the environment, are the most dangerous to health, especially when it comes to children. In turn, the true food contaminants are divided into substances of natural (biological) and chemical origin. biological food contaminants:
- bacterial toxins;
- botulinum toxins;
- mycotoxins (toxins of microscopic fungi);
- toxins unicellular and multicellular algae.
Chemical food contaminants:
- metals, these include mercury, lead, chromium, arsenic, cadmium, cobalt, tin, nickel;
- pesticides and their metabolites: organic insecticide, methyl bromide, etc.;
- nitrates, nitrites, polycyclic aromatic compounds, growth of farm animals, etc.;
- radioisotopes (isotope 1 of an element that emits radiation levels during its transformation into other element). The main route of food contamination by radioisotopes is the soil, where they soak up the plant, and then he and vegetable products enter the body. The greatest risk to health is of strontium 90 and cesium 137.
The degree of contamination of the food depends on the degree of pollution. Foreign substances that enter into it as a result of human activity, accumulate in the soil, air, water, and, therefore, moving up the chain, will inevitably enter the body and cause health problems. In terms of the distribution and toxicity of the most dangerous food contaminants are heavy metals, pesticides and their metabolic products, radionuclides, polycyclic aromatic hydrocarbons, nitrates, nitrites.
Food Safety on the content of chemicals and pollutants, veterinary drugs and medicines, as well as microbiological and radiation by their respective health standards set by the state of technical regulations and monitored by government agencies at all levels. So the acquisition of products in shops and public markets is a kind of guarantee of their security.
The degree of contamination of the food depends on the degree of pollution. Foreign substances that enter into it as a result of human activity, accumulate in the soil, air, water, and, therefore, moving up the chain, will inevitably enter the body and cause health problems. In terms of the distribution and toxicity of the most dangerous food contaminants are heavy metals, pesticides and their metabolic products, radionuclides, polycyclic aromatic hydrocarbons, nitrates, nitrites.
Food Safety on the content of chemicals and pollutants, veterinary drugs and medicines, as well as microbiological and radiation by their respective health standards set by the state of technical regulations and monitored by government agencies at all levels. So the acquisition of products in shops and public markets is a kind of guarantee of their security.
Nitrates and nitrites
In agriculture as highly fertilizer widely used of nitrate - nitrates, sodium, potassium, ammonium, and calcium. The process of getting to the soil nitrate is accompanied by accumulation of these compounds in plant tissues. Nitrates are toxic, but they are the precursors of N-nitroso compounds, carcinogenic effects, that is, predispose to the development of cancer. In grains and vegetables in wet conditions, as well as in the gastrointestinal tract microflora involving nitrates to nitrite (Nitrate). On admission of nitrite in the blood formed methemoglobin, which in contrast to the hemoglobin can not carry oxygen. At a concentration of methemoglobin in the blood of about 15% (slight degree of poisoning) appears lethargy, drowsiness. Symptoms of poisoning appear after 1-6 hours of receipt of nitrates in the body. Acute poisoning begins with nausea, vomiting, diarrhea, there is an increase, and tenderness to palpation of the liver, lower blood pressure. Pulse with irregular, weak, cold limbs, breathing quickens, headache, tinnitus, weakness, muscle cramps face, poor coordination, loss of consciousness, coma. Sodium nitrite is widely used as a preservative in the food industry in the preparation of sausages, canned meat, ie "Adult products" and are not used in the production of baby food. Avoid poisoning by nitrates in our power. Possible to reduce the concentration of harmful substances by heating does not use canned food. There are agricultural pollutants that intact into the environment, accumulate in plants, meat and fat of animals, and in the same unaltered enter the body, causing irreparable harm to health. In addition, all of these substances, unfortunately, able to penetrate into the breast milk, so the children are not immune from intoxication.
Dioxins
Dioxins are among the most hazardous environmental pollutants and food. They are by-products of the production of plastics, pesticides, paper. Dioxins are carcinogenic, immunotoxic, very stable in the environment, therefore, fall into animal feed, accumulate in their fatty tissue, milk and get into fat-containing products - oils, fats, meat, and milk. Particularly heavily contaminated with dioxins seafood because they are biological filters habitats, passed through a contaminated water. Common symptoms of prolonged exposure to dioxins are a wide variety of skin manifestations and neurological disorders, reproductive disorders. Can occur and symptoms - persistent heterogeneous rash, nervous conduction, the cause of which is very difficult to establish
Heavy metals
Heavy metals are widely distributed in nature and are continually being found in food. Most heavy metals are essential nutrients, and potentially dangerous to the health, ie toxic include cadmium, mercury, lead and tin. For all foods set limit values for heavy metals, and the appropriate authorities verify compliance. The presence of each metal in food is controlled by chemical analysis, and in the human body - maximum residue limits. Food contamination with heavy metals is due to industrial emissions and urban transport. Regular use of products with a high content of heavy metals will inevitably lead to disruption of many body systems (cardiovascular, respiratory, digestive, excretory, etc.), but for the majority of heavy metals there is no "specific" symptoms of poisoning and destruction of the body, making it difficult to identify the causes disease, and therefore the treatment. By handling food stuff - thorough washing, cleaning products, separation of low-value parts can be removed from 20 to 40% of heavy metals. Poisoning by toxic heavy metals - mercury, lead, tin, as a rule, is only possible in hazardous environments.
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