Ochratoxin A survey in Portuguese wine by LC-FD with direct injection

Abstract

Wine and grape juices were identified as one of the most important sources of ochratoxin A (OTA), a mycotoxin with diverse toxic effects that naturally appears in food and foodstuffs all over the world. The aim of this study was to assess the OTA levels in Portuguese wines through the application of a simple and accurate method based on liquid chromatography (LC) with direct injection, followed by fluorescence detection (FD). Randomly selected wine samples were used to evaluate the performance of direct injection as efficient, fast, inexpensive and safe sample preparation method. The proposed method was successfully validated. The limit of quantification (LOQ) was 1.0 microg/L and OTA recoveries from wine samples, spiked at the three fortification levels, were higher than 85.4%, with RSDs lower than 9.6% for both red and white wines. The presence of OTA was confirmed by methyl ester derivatization followed by LC analysis. Data on OTA levels were obtained for 60 Portuguese red and white wine samples. OTA was found in 12 samples, nine (26%) red wine samples and three (12%) white wine samples. Only one red wine sample and one white wine sample presented a contamination level above the LOQ, with 1.23 and 2.4 microg/L, respectively. It should be pointed out that this white wine sample exceeded the EC maximum permitted level of 2.0 microg/L. The safe dose established as 120 ng/kg body weight/week was not exceeded by the weekly intake estimated for the samples contaminated above the LOQ.