Chapter 69 - Aflatoxins

Abstract

Worldwide, aflatoxins (AFs) present a major food and feed safety issue. All vertebrate species studied are susceptible to AFs. The important aflatoxigenic species of fungi identified are Aspergillus flavus, Aspergillus parasiticus, and Aspergillus nomius. The aflatoxigenic fungi produce various members of the AF group of chemicals (AFB1, AFB2, AFG1, and AFG2) and other mycotoxins. Preharvest Aspergillus growth and contamination of crops with AFs can be endemic in certain areas. It is generally linked to adverse growing conditions, pest and hail damage and fungal growth during transportation and storage. The distribution of AFs in the transported or stored foodstuffs-feedstuffs can be highly heterogeneous. Although regulated by most governments, animals and humans can have unprotected oral exposure to AFs. AFB1-epoxide metabolite forms DNA, RNA, and protein adducts. The most potent naturally occurring carcinogen targeting the liver is AFB1. Additionally, AFs are hepatotoxic, immunotoxic, and cause adverse reproductive effects. The toxic metabolites of AFs are excreted in milk, including breast milk, and can be present in other edible animal products. The negative interactive effects of AFs with infectious diseases have been demonstrated. It is unlikely that field exposures of humans and animals to AFs occur without other mycotoxins also being present in the foodstuffs or feedstuffs, respectively. Other mycotoxins can increase the toxicity of AFs.