MYCOFLORA AND MYCOTOXINS IN DRY BEAN (PHASEOLUS-VULGARIS) PRODUCED INTAIWAN AND IN ONTARIO, CANADA

We undertook a comparative investigation of mycoflora and mycotoxins i n dry bean (Phaseolus vulgaris) produced in Taiwan and Ontario. Seedbo rne fungi were isolated and characterized. A profile of bean mycoflora was developed for each region having distinct climatic conditions. Th e frequency of various isolated fungi was also determined. The average percentages of seedborne fungi in the bean lots from Ontario and Taiw an were 54.8 and 58.5%, respectively. The fungi most-frequently isolat ed from the diseased Ontario beans were Alternaria (61.1%), Fusarium ( 18.0%), Rhizoctonia (6.1%), Penicillium (5.2%), Rhizopus (3.2%), Scler otinia (3.0%), Gliocladium (2.2%): and Mucor (1.7%). The fungi most-fr equently isolated from the diseased Taiwan beans were Aspergillus (48. 5%), Penicillium (27.6%), Eurotium (6.7%), Rhizopus (5.3%) and Curvula ria (2.4%). Based on these profiles, Fusarium and Aspergillus were ide ntified as the most-probable mycotoxin-producing fungi in the bean lot s from Ontario and Taiwan, respectively. Subsequent analyses were made of the fungal-infected and non-infected beans from each region. The i nfected beans from Ontario contained the fusarium toxins diacetoxyscri penol, deoxynivalenol, T-2 toxin and fumonisin B-1, but no aflatoxins. The infected beans from Taiwan contained aflatoxins B-1, B-2, G(1), a nd G(2), but no fusarium toxins. In the non-infected bean samples from both regions, however, neither fusarium toxins nor aflatoxins were de tected. The monitoring of mycotoxins in imported beans can be simplifi ed by developing a profile of the mycoflora from each exporting countr y. The profile can help to narrow the range of mycotoxins to be detect ed. A similar approach can be taken for other field crops.