Fungal contamination and Aflatoxin B1 and Ochratoxin A in Lebanese wine–grapes and musts

Five hundred and ten strains of filamentous fungi were isolated from Lebanese grapes during 2005 at veraison and harvesting periods. Four hundred eighty-seven isolates belonged to the Aspergillus spp. (95.5%) and 23 belonged to the Penicillium spp. (4.5%). Black aspergilli constituted 56.9% (52.2% Aspergillus niger aggregates, 2.9% Aspergillus japonicus and 1.8% Aspergillus carbonarius) while the isolation rate of Aspergillus flavus the none habitual member of grape mycobiota was 43.1% of the total Aspergillus spp. isolated. All isolates were tested for the ability to produce the Ochratoxin A (OTA) and the Aflatoxin B1 (AFB1). A. carbonarius showed that it is the only species able to produce the OTA with a production ability of 100% and a maximum concentration reaching 8.38 μg/g CYA. As for the aflatoxigenic ability, 43.4% of A. flavus isolates produced this mycotoxin with a maximum production reaching 22.6 μg/g CYA while none of the other isolates showed a production capacity of this mycotoxin. Forty-seven samples of must produced from the collected grapes were also analyzed. None of these samples was contaminated by OTA at a detectable limit while 40% of these same samples were found to contain AFB1 with concentrations ranging from 0.01 to 0.46 μg l−1.