Characters of aflatoxigenic fungi isolated from silkworm frass and tea field Soil in Japan

Abstract

Distribution of aflatoxigenic fungi in Japan has been studied extensively because of safety concerns about traditional fermented foods which use A. oryzae or A. sojae for the fermentation. Very limited distributions of these fungi in the warm areas of southwest Japan were reported. Later, Takahashi isolated aflatoxigenic fungi from field soil samples in Kanagawa Prefecture and Goto et al. isolated some aflatoxin producing fungi from silkworm frass including samples collected in the northern part of Japan. However details of these fungi have not been published. Recently, we isolated some aflatoxigenic fungi, all from Aspergillus section Flavi, from acidic tea field soil samples. All aflatoxigenic fungi previously known belonged in A. flavus, A. parasiticus and A. nomius but the recent isolate we reported on produces aflatoxin and cyclopiazonic acid, but is similar morphologically to A. tamarii. Also, aflatoxigenic species from Aspergillus sections other than Flavi have been reported. Important non-aflatoxigenic strains and species from section Flavi include A. oryzae, A. sojae, A. tamarii and A. caelatus.