Incidence of Toxic and Other Mold Species and Genera in Soybeans.

The mold flora of 385 unprocessed soybean samples was determined before and after surface disinfection of the beans with 5% NaOCl. Molds were detected in 99.4% of the 19,250 non-disinfected soybeans examined, and in 52.8% of the 19,250 surface-disinfected soybeans examined indicating that contamination was primarily at the surface, although internal invasion also was substantial. The mold flora, both before and after surface disinfection, was dominated by species of the Aspergillus glaucus group, Asperigillus flavus , Aspergillus candidus , Penicillium cyclopium , plus species of Alternaria and Cladosporium . The toxicogenic species A. flavus , Aspergillus nidulans , Aspergillus ochaeceus , Aspergillus versicolor , Penicillium citrinum , P. cyclopium , and Pencillium viridicatum were encountered regularly in non-surface-disinfected soybeans. Except for A. flavus and P. cyclopium , the occurrence of toxicogenic species Aspergillus melleus , soybeans was sporadic. The toxicogenic species Aspergillus melleus , Pencillium expansum , and Penicillium urticae were encountered occasionally, but only in non-surface-disinfected soybeans. Penicillium chrysogenum , the penicillin-producing organism, was encountered regularly in non-surface-disinfected soybeans, but less frequently in disinfected soybeans.