Aflatoxins are a group of naturally occurring mycotoxins produced by two types of Aspergillus mold, which is found both on certain types of grains and in the soil. There is great health concern over aflatoxins because of their high level of toxicity to humans and their potent carcinogenic effect in laboratory animals.

Mycotoxins are secondary metabolic products of molds. These compounds are called secondary metabolites because they are not required for growth but are a product of the primary metabolic processes. Aflatoxins are the most commonly occurring and most studied mycotoxins in feedstuffs worldwide. Aflatoxins have been identified in corn, cottonseed, peanuts, and peanut products and tolerances for these products have been set in the 20 to 200 parts per billion range. Testing of these products is important for both human consumption as well as for use in livestock feeds.

Because it is necessary to test for aflatoxins at such a low level, special analytical techniques are often required. Perhaps the most important step is the “clean-up” step, where the aflatoxins are removed from the bulk part of the sample. This is accomplished through a series of solvent extractions, solid phase extractions and immunoaffinity column assay.

The detection method for aflatoxins is molecular fluorescence spectroscopy. For determination of individual aflatoxins (B1, B2, G1, G2 are the four most common), HPLC is used for separation. For determination of total aflatoxins, fluorescence spectroscopy can be used directly.