Testing Methods for Aflatoxins in Foods

Abstract

Aflatoxins, a group of mycotoxins produced mainly by Aspergillus flavus Link ex Fries and A. parasiticus Speare, have been recognized as one of the major contaminants of food throughout the world. Because of their acute hepatocarcinogenic nature, these groups of fungal food contaminants have received considerable attention in recent years. Several analytical and immunological methods are available for testing and estimating aflatoxins in different food commodities. However, most of these analytical methods are actually minor modifications of the basic methods officially adopted for specific commodities. They differ only in the solvents used to extract the toxins and in the techniques used for estimating the intensity of fluorescence of the analysed toxins. All analytical methods for aflatoxins involve basically the same steps: sampling and sample extraction, clean-up, work-up, detection, and confirmation, as well as estimation of the toxin. Various types of high-performance chromatographic approaches are most commonly used. A rapid qualitative assessment has also been reported with the help of minicolumn methods. By using monoclonal and polyclonal antibodies, several sensitive and specific enzyme-linked immunosorbent assays (ELISA) and radioimmunoassays (RIA) have been developed for aflatoxin analysis. ELISA techniques are more rapid, more sensitive, and simpler to use than the conventional analytical methods. Several commercial ELISA-based aflatoxin kits using monoclonal antibodies are also available for aflatoxin analysis.