WINGED BEAN (PSOPHOCARPUS-TETRAGONOLOBUS (L) DC) AS A SUBSTRATE FOR GROWTH AND AFLATOXIN PRODUCTION BY AFLATOXIGENIC STRAINS OF ASPERGILLUS SPP

The mold flora of seeds of 12 varieties of winged beans was determined both before and after surface disinfections. When seeds were surfaced disinfected, mold fungi were detected in 73% of the seeds whereas 81% of the seed that was not disinfected produced mold fungi. Aspergillus spp. was most frequently present while Penicillium spp. occurred in seed of 4 varieties and in < 4% of the seed. Twelve isolates of A. flavus and A. parasiticus were examined for their ability to produce aflatoxins. Whether aflatoxins were produced and the amount of each varied according to the origin of the isolate and the species of Aspergillus. For example all A. parasiticus isolates produced at least 2 aflatoxins whereas 4 of the A. parasiticus isolates were non-toxigenic. When ground seeds of winged beans were inoculated with an aflatoxigenic strain of A. parasiticus the level of aflatoxins that occurred varied with the variety; however, the level of aflatoxin was higher in winged bean than in peanut tissue and 6 of 12 winged bean varieties contained higher levels of aflatoxin than rice.