Ochratoxin A in table wine and grape-juice: occurrence and risk assessment

The concentrations of ochratoxin A (OA) and C (ethyl ester of OA, OC) have been measured in table wine from the Swiss retail market. The overall median concentrations of OA in white, rose and red table wine were (number of samples; range) < 3 pg/ml (24; < 3-178 pg/ml), 19 pg/ml (15; < 3-123 pg/ml) and 13 pg/ml (79; < 3-388 pg/ml)), respectively. For dessert wines (Malaga, Marsala) a median of 337 pg/ml (5; 44-451 pg/ml) resulted. Concentrations of OC were about 10% of those of OA. OA has been detected in red grape-juices for the first time with median concentrations amounting to 235 pg/ml (8; < 3-311 pg/ml). White grape-juices (3) as well as other fruit juices (2 apple, 6 orange, 2 others) did not contain OA (< 5 pg/ml). The analytical method used was not appropriate for grapefruit-juices because of an interfering substance. The results indicate that OA is formed prior to the alcoholic fermentation. It also appears that the more southerly in Europe is the origin of the samples the higher is the frequency of occurrence and the concentration of OA in red wines and red grape-juices. Although the estimated mean daily OA intake of 0-7 ng/kg body mass (men) can easily be more than doubled by moderate wine consumption, an additional health risk by OA is not to be expected. On the other hand the consumption of red grape-juices among infants and children may result in intakes high enough to justify a reduction of the OA concentrations in these juices to less than 100 pg/ml.