When food is moldy and spoiled, mycotoxin will be secreted. People who eat moldy food are prone to diarrhea, vomiting and other symptoms. After a long time, it will cause cancer of cells, leading to cancer. Moreover, mycotoxin has strong chemical and physical stability, and it is difficult to remove the harm of mycotoxin to human body through simple processing and cooking. There are many kinds of molds, which are widely distributed in nature, and most of them are harmless to human body. However, some toxic strains of mold will produce toxic metabolites and mycotoxins after polluting food. At present, there are more than 200 kinds of main molds and their toxins, but the main ones that are closely related to food and have serious harm are aflatoxin, yellow rice toxin, penicillin toxin and Fusarium toxin, cyclophosphamide, sterigmatocystin and F-2 toxin. Aflatoxin, especially aflatoxin B 1, is an internationally recognized carcinogen.

Aflatoxin includes: B 1, B2, G 1, G2, M 1, M2, P 1, Q 1, toxol, H 1, GM, etc. They are similar in structure and highly toxic. Generally, it is stable in neutral and acidic solvents, and decomposes rapidly in strong alkali solvents with pH of 9- 10, with strong heat resistance. Aflatoxin is generally difficult to be destroyed at cooking heating temperature, and it can only be completely destroyed when it is heated above 280 degrees. Aflatoxin mainly pollutes grain and its products. In addition, various plant and animal foods may also be widely polluted, such as peanuts, corn, rice and cottonseed. There are also beans such as sheaths, almonds, hazelnuts, sorghum, wheat and soybeans, and eggs, milk, liver and dried salted fish will also be polluted.

Expired food will not only go moldy and deteriorate, but also be polluted by other things, such as rats and pests, which will also pose a threat to human health. If the food is exposed to rats and pests, the packaging bag will burst, right? Will it be sold again? As exposed in 3. 15, if there are bugs, filter them out and continue to sell them in another package. Changing the bag after being bitten by a coated mouse will spread the disease to people.