New Methods for Rapid Detection of Aflatoxin

The rapid detection of mycotoxin contamination in agricultural commodities is an area of research that requires more attention. The many companies buying hundreds of bushels of cereal grains daily, need to inspect their purchases immediately and to make a decision in minutes. Arising from this need to detect aflatoxin, we have developed two methods for rapid identification of aflatoxin in corn. The first is based upon a glowing greenish-gold fluorescence produced under ultraviolet light (365 nm) by corn kernels that contain aflatoxin. The fluorescent material is not aflatoxin hut a compound associated with it. Fluorescence depends upon the interaction between enzymes in corn and a compound produced by members of the Aspergillusfiavus series. Heatsterilized corn inoculated with A. parasilicus does not fluoresce, although aflatoxin is formed. Fluorescence is seen in broken kernels but it is not visible in intact corn kernels until they are broken. Laboratory studies show that this method of detection is applicable for other cereals, including wheat, rice, oats and barley, but is apparently not effective for soybeans and peanuts. The second is a modification of the chromatographic mini-column method devised for corn. The rapid detection of mycotoxin in contamination of agricultural commodities and products is an area of research that requires much more attention. Elevator operators, grain buyers and processing companies buy thousands of bushels of cereal grains daily, and in buying, they need to inspect their purchases immediately and to make a decision in minutes. To give you an idea of the magnitude of this problem, remember that this year the corn crop in the United States is estimated to be more than 5 billion bushels. In response to the need to detect aflatoxin rapidly in corn (maize), we have developed two methods within the past year. Until 1971, levels and incidence of aflatoxin detected in corn from commercial markets caused no alarm. The levels of contamination were less than 50 ppb. However during 1971, it became apparent that a problem did exist, at least for that crop year, in certain areas where white corn is grown. During our earlier corn surveys, we had hoped to make a visual observation of grains that would enable us to detect toxin-contaminated grains. We Agricultural Research Service, US Department of Agriculture. Mention of firm names or trade products does not imply that they are endorsed or recommended by the Department of Agriculture over other firms or similar products not mentioned.