Aflatoxin (AFT) is a bifuran ring toxoid and produced by some strains of Aspergillus flavus and parasitic Aspergillus. There are about 20 derivatives, named B1, B2, G1, G2, M1, M2, GM, P1, Q1, toxinol, etc. Among them, B1 is the most toxic and carcinogenic. After the animals eat the feed polluted by aflatoxin, a very small amount of aflatoxin can be detected in the liver, kidney, muscle, blood, milk and eggs. Aflatoxins and their producing bacteria are widely distributed in nature. Some strains produce more than one type of aflatoxins, and there are also strains that do not produce any type of aflatoxins. Aflatoxin mainly pollutes grain and oil products, and all kinds of plant and animal food can also be polluted.