| Summary: | The natural presence of OTA in wine has been reported worldwide. However, this is the first investigation that has demonstrated the co-occurrence of several ochratoxins in 51 red wines from Navarra (Spain) and 96 samples from 8 Mediterranean countries. This fact is partly due to the low limits of detection and quantification obtained.
An HPLC-FLD analytical method was developed and validated for the simultaneous quantification of ochratoxin A (OTA), ochratoxin B (OTB) and their methyl and ethyl esters (methylochratoxin A (MeOTA), ochratoxin C (OTC), methylochratoxin B (MeOTB) and ethylochratoxin B (EtOTB)) in red wine.
No samples exceeded the 2 µg/L maximum permitted by the EU for OTA in wine. Simultaneous occurrence of OTA and OTB were found in 100% of the samples. In addition, 90% of the Mediterranean wines presented OTC and the six ochratoxins were detected in 45%. OTA-OTB and OTA-OTC concentrations showed a very large positive association between each other. In general, levels were not influenced by the country of origin except in the case of Tunisia and Algeria, whose concentrations were statistically higher.
Some factors that could affect the ochratoxin levels were investigated. In general, no significant differences were found between vintages. With the exception of OTA, no significant differences were observed between organic and traditional farming. Concentrations were positively correlated with temperature and inversely correlated with humidity and rainfall during the summer prior to grape harvesting.
OTC transformation into OTA in red wine was also examined. The results obtained suggested that OTC hydrolyzed to OTA in wine.
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