| Abstract: | There had been a growing body of circumstantial evidence that aflatoxin B1 is carcinogenic, as well as acutely toxic, to humans, but in 1987 that International Agency for Research on Cancer (IARC) of the World Health Organization (WHO) accepted that aflatoxin should be classified as a Group 1 carcinogen. Regulatory levels set by the governments of many countries are based on the premise that aflatoxin is indeed carcinogenic and the European Community agreed on 16 July 1998 a limit of 2 μg kg−1 for aflatoxin B1 in a range of foods for human consumption. The need for a risk assessment arises from the widespread occurrence of the aflatoxins in commodities resulting from contamination in storage and in the field by the fungi which produce it—Aspergillus flavus, A. parasiticus and A. nomius. Risk assessment requires both a knowledge of exposure and a detailed knowledge of the toxicology of the aflatoxins. The toxicology of aflatoxin B1 involves a complex sequence of metabolic alterations of the molecule by enzymes in the animal tissues (usually the liver). This complexity is reflected in the very diverse range of responses by different animal species and it is likely that there will also be differences in response amongst different races of humans, and indeed even amongst different individuals of the same race. |
