Mycotoxins produced by certain Aspergillus moulds, most commonly Aspergillus flavus and Aspergillus parasiticus. The major forms of aflatoxins are aflatoxin B1, aflatoxin B2, aflatoxin G1 and aflatoxin G2. Aflatoxin B1 is the most common and most toxic in both animals and humans. It is a carcinogen so out of all the mycotoxins is the most regulated in both animal feedstuffs and human foods. Cattle convert aflatoxin B1 to aflatoxin M1.