For definition of Groups, see Preamble Evaluation. Aflatoxins are a group of relatively stable toxins produced mainly by two Aspergillus species that are ubiquitous in areas of the world with hot, humid climates. Whether exposure is predominantly to aflatoxin B1 or to mixed B1 and G1 depends on the geographical distribution of the Aspergillus strains.
Exposure occurs primarily through dietary intake of maize and groundnuts.
Exposure to aflatoxin M1 occurs mainly through consumption of milk, including mother's milk. Life-time exposure to aflatoxins in some parts of the world, commencing in utero, has been confirmed by biomonitoring. 5.2 Human carcinogenicity data One cohort study of a small number of Dutch oilpress workers exposed to aflatoxin-containing dusts indicated increased mortality from cancer, but no death from hepatocellular carcinoma was observed. A cohort study in China found significant excess mortality from liver cancer among individuals in villages where foods were heavily contaminated with aflatoxins. A cohort study of Danish workers exposed to aflatoxin from imported feed found an excess of hepatocellular carcinoma among those who had had major exposure to aflatoxin-contaminated feed in the period 10 or more years before diagnosis.