Aflatoxins and ochratoxin A and their Aspergillus causal species in Tunisian cereals.

Occurrence of aflatoxins (AFs) AFB1, AFB2, AFG1, AFG2 and ochra toxin A (OTA) was studied in 65 samples of stored and freshly harvested wheat, barley and maize collected in Tunisia. The mycotoxins were simultaneously extracted and quantified by high performance liquid chromatography. Determination of AF-producing (sectionFlavi)and OTA-producingAspergillusspecies (sectionsNigriandCircumdati) was conducted in these samples by species-specific polymerase chain reaction (PCR). Results showed that most of maize samples were contaminated with AFs, data after storage showing lower values than those collected at harvest. All contaminated maize samples contained AFG1 and AFG2, among which 27.78% also had AFB1 and AFB2. This AFs pattern was consistent with theA. parasiticustoxin profile.A. flavushowever showed the highest frequency in maize but was also found in barley and wheat where no AFs were detected. In contrast, OTA was neither found in maize nor in barley and only one wheat sample contained OTA.A. nigerwas the only OTA-producing species detected. [ABSTRACT FROM PUBLISHER]