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 B 1 or to mixed B 1 and G 1 depends on the geographical distribution of the Aspergillus strains .
Exposure occurs primarily through dietary intake of maize and groundnuts.
Exposure to aflatoxin M 1 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.