Mycobiota and ochratoxin A in raisins purchased in Hungary

Ochratoxin A is a mycotoxin produced by Aspergillus and Penicillium species. This mycotoxin is a common contaminant of various foods including cereal products, spices, dried fruits, coffee, beer and wine. Besides cereal products, goods of grape origin contribute significantly to ochratoxin exposure of humans. The ochratoxin content and mycobiota of raisins purchased in Hungarian outlets were examined in this study. Ochratoxin A content was examined by an immunochemical technique, and the results were confirmed by HPLC analysis using fluorescent detection. Altogether 20 raisin samples were analyzed. Ochratoxin A was detected in all but two samples with ochratoxin concentrations ranging from 0 to 6.2 mg kg-1. The most heavily contaminated raisin sample came from Iran. However, none of the raisins contained ochratoxin A above 10 mg kg-1, the European Community maximum allowable limit in raisins. The mycobiota of raisin samples was also examined to clarify which species could be responsible for ochratoxin A contamination. All except three raisin samples were contaminated with black aspergilli, some of which produced ochratoxin A. Besides A. carbonarius, ochratoxin producing A. tubingensis isolates dominated in the samples.