ANALYSIS OF NATURALLY-OCCURRING MYCOTOXINS IN FEEDSTUFFS AND FOOD

Aflatoxins, zearalenone, deoxynivalenol, fumonisins, and their respective metabolites require specific procedures for their determination because of their diverse chemistry and occurrence in complex matrices of feedstuffs and foods. Major sources of error in the analysis of these mycotoxins arise from inadequate sampling and inefficient extraction and cleanup procedures. The determinative step in the assay for each of these toxins is sensitive to levels below those that are considered detrimental to humans and animals. Aflatoxins can be determined in grains and animal fluids and tissues by TLC, HPLC, gas chromatography-mass spectrometry (GC-MS), and ELISA procedures. Zearalenone, an estrogenic mycotoxin, can readily be determined in cereal grains and foods by HPLC (50 ng/g) and by TLC (300 ng/g). No incurred levels of zearalenone or its metabolites have been detected in animal tissues destined for human consumption. Deoxynivalenol can be determined in wheat and corn at 300 ng/g by a rapid TLC procedure and at 325 ng/g by a GC method. Although not tested collaboratively, an HPLC procedure and an ELISA screening procedure are capable of detecting deoxynivalenol at low (nanograms/gram) levels in feedstuffs and foods. The recently characterized fumonisins can be detected by TLC, HPLC, and GC-MS at levels below those now considered harmful. Thin-layer chromatography and HPLC (with fluorescence detection of derivatives) procedures can detect fumonisins at approximately 100 ng/g; G-C-MS is required for detection at lower levels.