Aflatoxin Detection and Determination in Corn

There are three approaches to aflatoxin detection in corn: (1) a presumptive test that can be done in the field to determine whether a corn lot should be analyzed for aflatoxin or not; (2) rapid screening methods to establish the presence or absence of toxin: and (3) quantitative methods to detennine toxin levels. The presumptive test for aflatoxin in corn is the black light test or the bright greenish-yellow fluorescent test based on the fluorescence under ultraviolet light (365 nm) associated with Aspergillus flavus or A. parasiticus. Rapid screening tests have included minicolumn methods that can be done in a laboratory with minimal facilities and thin-layer chromatography (TLCl. Determination of aflatoxin levels involves extraction, purification ofthe extract, and measurement of the toxin by TLC using visual comparisons with a standard or densitometry or high-pressure liquid chromatography. A fluorometric-iodine method has been used both for screening purposes and for quantitation of aflatoxin in corn.