Survey of Vietnamese coffee beans for the presence of ochratoxigenic Aspergilli.

Vietnamese coffee beans were investigated for the presence of ochratoxigenic Aspergilli. Ninety-three percent of the coffee samples studied were positive for A. niger. No other ochratoxigenic species were present. HPLC analysis determined that 8.7% of the A. niger strains were positive for ochratoxin A (OA) production. There was no significant difference in the level of contamination or incidence of toxigenic strains in samples that had been rejected by manual sorting and those that were destined for human consumption. No OA-producing fungi were uncovered in a fresh coffee bean sample analysed, suggesting that the OA problem most likely occurs post-harvest.