Prevention of aflatoxin in pistachios1

Awareness that undesirable levels of aflatoxin in food and feed may have serious consequences for human and animal health is increasing. Aflatoxins, probably the most studied and widely known mycotoxins, were first noted in the early 1960s. They are among the most potent mutagenic substances known; there is extensive experimental and epidemiological evidence that they induce liver cancer (WHO, 1998). The term aflatoxin refers to a class of chemical compounds of related structure; among these aflatoxin B1 is considered to be the most potent carcinogen. The major aflatoxin-producing fungi are Aspergillus flavus and Aspergillus parasiticus. Under favourable temperature and humidity conditions these fungi grow on certain foodstuffs, most commonly groundnuts, dried fruit, tree nuts (almonds, pecans, walnuts, pistachios and Brazil nuts), spices and a range of cereals (especially maize). Production of aflatoxin is optimal at relatively high temperatures, so contamination is most acute and widespread in warm, humid climates. Although contamination is generally considered to be a problem in tropical and subtropical regions of Africa, Asia and Latin America, aflatoxins have also been found in temperate countries of Europe and North America (FAO, 1979, 1982).