Determination of ochratoxin A in red wine and vinegar by immunoaffinity high-pressure liquid chromatography

A method is described for the determination of ochratoxin A (OTA) in red wine and vinegar using an acidic chloroform extraction, an immmunoaffinity clean-up step, and a high-performance liquid chromatographic determination with fluorescence detection. The detection limit was estimated at 0.002 microg/liter. The mean recovery factors were found at 91.3 and 96.6% for wine and vinegar, respectively. Thirty-one samples of red wine originating from Mediterranean sea countries and 15 samples of vinegar were examined for the presence of OTA. All red wine samples contained OTA. Seventy-two percent of these samples were found to be contaminated over 0.1 microg/liter. Among them, nine samples contained ochratoxin A in the range of 0.5 to 3.4 microg/liter, 12 samples in the range of 0.10 to 0.50 microg/liter (median: 0.176 microg/liter), and 9 samples in the range of 0.010 to 0.100 microg/liter (median: 0.041 microg/liter). All 15 vinegar samples showed the presence of OTA. The most contaminated ones were three balsamic vinegar samples containing 0.156 microg/liter, 0.102 microg/liter, and 0.252 microg/liter of OTA. In the remaining 12 samples, ochratoxin A levels ranged from 0.008 microg/liter to 0.046 microg/liter (median: 0.012 microg/liter). These data are in good agreement with the hypothesis that wine originating from Southern countries might contain significant OTA concentration and showed the possible occurrence of traces of OTA in vinegar.