The survey of 22 commercial samples of imported green coffee beans for aflatoxins and ochratoxin has been conducted in 1982-1983. Ochratoxin A was detected in 4 samples at a level of 9.9-46μg/kg but all samples analyzed were negative for aflatoxins. Major contaminants of the samples were Aspergillus glaucus group, A, niger group, A. flavus group, A. ochraceus group and members of the Mucorales. Among the contaminants, the ability of A, flavus and A, ochraceus isolates to produce the mycotoxins was examined. Particularly, 9 isolates of A. ochraceus group produced high levels of ochratoxin A on artificial polished rice and ground coffee media (yields of ochratoxin A: 48.3-750μg/g on rice and 8.06-130μg/g on coffee, respectively). Addition of caffeine (0.1-1.0%) on MY-20 agar medium in a Petri dish resulted the delayed growth of A. ochraceus strain S-235-100, a representative isolate from the green coffee beans, but had little effect on its ochratoxin production. On the basis of the results obtained in this study, it is apparent that green coffee beans might be susceptible to A, ochraceus infection and subsequent ochratoxin production.
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