Fungal contamination of rice from south Vietnam, mycotoxinogenesis of selected strains and residues in rice

25 samples of Vietnamese rice coming from the Mekong delta were analysed fo r fungal contamination. Ergosterol content measurement and total fungal loa d determination revealed that moulds contamination was quite weak. Identifi cation of fungal species revealed that Aspergillus genus was the most impor tant (43.75% of isolates) followed by Fusarium (21.8%) and Penicillium (10. 9%). This analysis also revealed the presence of toxigenic strains such as Aspergillus flavus, A. ochraceus and Penicillium citrinum. These strains we re tested for their toxinogenic potential on either YES liquid medium or on autoclaved rice. 80% of A. flavus strains were able to produce cyclopiazon ic acid (levels up to 32.3 ppm), all strains of A. ochraceus synthesised oc hratoxin A (one at 178 ppm) and the tested strain of P. citrinum was modera tely toxigenic for citrinin. Moreover two rice samples were found contamina ted with high level of ochratoxin A (21.3 and 26.2 ppb). Such contamination can probably be linked to unfavourable post harvest storage and climatic c onditions.