Ochratoxin a occurrence in Greek dry and sweet wines

Aims : To assess ochratoxin A (OTA) presence in Greek wines, according to the production area and the technology, as OTA risk is higher in wines from southern Europe. The effect of fining agents was examined in order to investigate OTA reduction. Methods and results : Dry and sweet wines issued from research programs and trade wines were analyzed, according to the official HPLC method. Greek dry wines do not exceed the European limit of 2 ng/mL. The amount of OTA (in ng/mL) varies between 0 - 1,18 for dry white wines, 0 -1,00 for dry red wines. Among sweet wines, only fortified wines without alcoholic fermentation range between 0,50 -7,64, while other sweet wines range between 0,05 -1,73. Dry yeast reduced OTA by 25 - 60 % according to dosage and duration (1-10 weeks) while the effect of bentonite was 33 - 40 % reduction for a treatment of 3-6 days. Conclusion : The picture for Greek wine production is positive, even in case of a future lowering of the European limit. OTA risk seems higher in the islands, particularly for some dessert wines. Results from wine treatment with fining agents support the theory of OTA adsorption onto suspended solids and the beneficial effect of yeast presence. Significance and impact of study : Assessment of OTA danger for Greek wines and information concerning the effect of fining agents contribute to the production of wines free from contaminants and support wine economy.