Review on the natural co-occurrence of AFB1 and FB1 in maize and the combined toxicity of AFB1 and FB1

Mycotoxins rarely occur individually in foodstuffs and are considered a food safety risk, particularly for highly consumed foods like maize. Aflatoxin B1 (AFB1) and fumonisin B1 (FB1) are two of the toxicologically most relevant mycotoxins occurring in maize. Their co-occurrence in field and stored maize is described in this review, and the highest co-occurrence rate is observed in stored maize. In all reviewed studies, fumonisin B1 levels exceed aflatoxin B1 levels and in some cases even by up to a thousand fold. Co-occurrence and subsequently combined exposure of AFB1 and FB1 is of public health concern given that both in-vivo and in-vitro scientific evidence exists that various toxicological effects caused by combined exposure occur. In the majority of the studies reviewed in this paper the data suggest a modulation of the toxic effects of aflatoxin B1 and fumonisin B1 ranging from increased carcinogenicity, immunotoxicity and decreased growth in various animal species and cell lines. The emerging scientific data indicating the modulatory effects of combined exposure to aflatoxin B1 and fumonisin B1 is a sound basis for further investigation of the effects of combined exposure and the subsequent human health risk.