Biological pollution of food includes microbial, parasite, insect and virus pollution. Microbial pollution mainly includes bacteria and bacterial toxins, molds and mycotoxins. Bacteria in food include not only pathogenic bacteria that can cause food poisoning and zoonotic infectious diseases, but also non-pathogenic bacteria that can cause food spoilage and can be used as a sign of food pollution. Parasites and eggs mainly pollute food indirectly or directly through the feces of patients and sick animals and through water or soil. Insect pollution mainly includes beetles, mites and moths in grain, flies and maggots in animal food and fermented food. Virus pollution mainly includes hepatitis virus, polio virus and foot-and-mouth disease virus, and other viruses are not easy to reproduce in food.

2. Chemical pollution

The chemical pollution of food involves a wide range and the situation is complicated. It mainly includes: ① pollutants from production, life and environment, such as pesticides, veterinary drugs, toxic metals, polycyclic aromatic hydrocarbons, n- nitroso compounds, heterocyclic amines, dioxins and trichloropropanol. (2) Harmful substances dissolved in food when food containers, packaging materials and means of transport come into contact with food; ③ Abuse of food additives; ④ Substances produced during food processing and storage, such as harmful alcohols and aldehydes in wine; ⑤ Substances added in the process of adulteration and falsification.

3. physical contamination

It mainly comes from all kinds of complicated non-chemical sundries. Although some pollutants may not threaten the health of consumers, they seriously affect the sensory characteristics and/or nutritional value of food, and the quality of food cannot be guaranteed. They mainly include: ① pollutants produced in the process of food production, storage, transportation and marketing, such as grass seeds mixed in grain harvest, sundries in liquid food containers, dust and flies in the process of food transportation and marketing; (2) food adulteration, such as grain mixed with sand and gravel, meat injected with water, milk powder mixed with a lot of sugar; ③ The radioactive pollution of food mainly comes from the mining, smelting, production and application of radioactive substances and the pollution caused by accidents.

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I. Food pollution

1, the concept of food pollution

Food pollution refers to the process that some toxic and harmful substances enter normal food.

2. Classification of food pollution

According to the nature of foreign pollutants, food pollution can be divided into three categories: biological pollution, chemical pollution and radioactive pollution.

3. The impact of food pollution on human health

(1) acute toxicity

Contaminants enter the human body with food, causing damage to the body in a short time and producing clinical symptoms (such as acute gastroenteritis), which is called acute poisoning. The pollutants that cause acute poisoning are bacteria and their toxins, molds and their toxins and chemical poisons.

(2) Chronic toxicity

Food is polluted by some harmful substances, although the content is very small, but it will cause damage to the body after several years, ten years or even decades due to long-term intake and accumulation in the body, showing various symptoms of chronic poisoning, such as chronic lead poisoning, chronic mercury poisoning, chronic cadmium poisoning and so on. It will have a subtle influence on children and adults, and only after a long period of time will it have obvious effects.

Children: The development of childhood is the most important and critical period in their life, because this period involves whether the various organs of the body are on a healthy body basis. The most important thing in childhood is to supplement enough food rich in protein, and then mineral elements (calcium, magnesium, zinc, etc. It's best to change the daily or weekly menu, give priority to vegetables and cereals, and supplement meaty food in moderation (of course, it's best to eat high-quality meaty food and eat less animals with artificial feed).

Women: In view of women's special physiological conditions, we should pay attention to foods rich in iron, and we should also supplement enough protein at ordinary times (because protein is conducive to relieving fatigue and enhancing physical function).

Old people: In the old age, the body function is in the least active state in life, so calcium food and protein food should be the main foods.

(3) Teratogenesis, Carcinogenesis and Mutation

Some food pollutants act on the embryo through pregnant women, which makes the cell differentiation and organ formation during development unable to proceed normally, leading to teratogenesis and even stillbirth. The teratogenic substances are pesticides such as ddt, sodium pentachlorophenol and carbaryl, and aflatoxin bl can also cause teratogenicity.

Chemicals and other physical or biological factors can lead to the growth of cancer in the body. At present, there are hundreds of substances suspected or carcinogenic, of which more than 90% are chemical factors, such as nitrosamines, aflatoxins, polycyclic aromatic hydrocarbons, arsenic, cadmium, nickel and lead, and 35% are related to diet.

3. Introduction to food pollution.

(1) aflatoxin pollution in food

(2) Benzo (а) pyrene pollution in food

Second, food poisoning.

1, concept

Food poisoning is an acute disease caused by people eating poisonous food.

2, the characteristics of food poisoning

Most patients (1) appear for a short time and are similar, and the onset is sudden and often explosive.

(2) All patients have similar symptoms of acute gastroenteritis.

(3) The incidence range is limited to a certain population. All patients have eaten the same or several kinds of food in a similar time, and the onset will stop immediately if they stop eating pathogenic food.

(4) High incidence and no infectivity.

3. Classification of food poisoning

1) bacterial food poisoning

2) Poisoning by poisonous animals and plants

3) Chemical food poisoning

4) Mycotoxin poisoning

4. Introduction of food poisoning.

(1) nitrite food poisoning

(2) Poisoning of puffer fish

(3) toadstool poisoning