Food itself should not contain toxic and harmful substances. However, in the process of planting or raising, growing, harvesting or slaughtering, processing, storing, transporting, and selling food before consumption, due to the action of environmental or human factors, food may be attacked by toxic and harmful substances and cause contamination. Reduce the nutritional value and hygienic quality of food. This process is food contamination.
Food is one of the three elements that constitute human life and health. Once food is contaminated, it will endanger human health. Food contamination refers to various foods people eat, such as grains, fruits, vegetables, fish, meat, eggs, etc., in the process of production, transportation, packaging, storage, sales, and cooking, mixed with harmful and toxic substances or germs.
To prevent food contamination, it is not only necessary to pay attention to dietary hygiene, but also to start from all aspects of production, transportation, processing, storage, and sales. Only in this way can the problem be solved fundamentally.
Biological contamination refers to the contamination of food by harmful viruses, bacteria, fungi and parasites. Bacteria and fungi belonging to microorganisms are invisible to the human eye. Eggs rot, vegetables rot, mainly bacteria and fungi are at work. There are many types of bacteria. Some bacteria, such as Proteus, Flavobacter, and Enterobacter, can directly contaminate animal food, and can also contaminate animal food through tools, containers, washing water, etc., causing food spoilage. There are many types of fungi, with more than 50,000 species. The first mold to serve human beings is a kind of fungi. Now, people eat fermented bean curd, sauce products are inseparable from mold. But more than 100 strains of them produce toxins, and the most toxic is aflatoxin. After food is contaminated with this toxin, it can cause primary liver cancer in animals. According to the survey, areas with high levels of aflatoxin in the food have dozens of times higher incidence of liver cancer than other areas. British scientists believe that breast cancer may be related to aflatoxin. The climate in East China and Central South China is warm and humid, and the pollution of aflatoxin is relatively common, mainly on peanuts and corn, followed by rice and other foods. The parasites that contaminate food mainly include roundworms, tapeworms, and trichinella. These parasites generally contaminate water sources and soil through the feces of patients and sick animals, and then contaminate fish, fruits, and vegetables. cause parasitic diseases.
The contamination of food by molds and their toxins is more common in rainy areas in the south. At present, there are about 200 kinds of mycotoxins known. Different molds have different toxin-producing abilities and different toxin toxicity. The mycotoxins that are closely related to food include aflatoxin, ochratoxin, variegated aspergillus, island penicillin, Huangtianjing, citrinin, stratum penicillin, trichothecenes, butenolactone, etc. After mold and mycotoxins contaminate food, there are two main hazards; that is, food spoilage caused by mold and human poisoning caused by toxins produced by mold. Mold-contaminated food can reduce the edible value of food, or even completely inedible, resulting in huge economic losses. According to statistics, an average of 2% of grains in the world are inedible due to mildew every year. Most of the poisoning caused by mycotoxins is caused by mold-contaminated grains, oil crops and fermented foods, and mold poisoning is often manifested as obvious local and seasonal.
There are many factors that affect the growth, reproduction and toxin production of molds. Conditions that are closely related to food include moisture, temperature, substrate, and ventilation. For this reason, controlling these conditions can reduce the damage caused by mold and toxins to food.