Low levels of ochratocin A in wines from Piedmont

Abstract

Ochratoxin A (OTA) is a mycotoxin mainly produced by a number of species of Aspergillus, commonly found in warm and tropical climates. OTA poses risks for the human health because of its nephrotoxic, teratogenic, immunotoxic and neurotoxic activity. The mycotoxin, classified as possible human carcinogen (Group 2B) by the IARC, naturally occurs in a wide range of foods, including wine, where the main producer is A. carbonarius. The aim of this work was the validation of a procedure for the analysis of OTA in Piedmontese red and white wines produced after vintage 2003 and 2004, in relationship with the limit of 2.0 microg l(-1) introduced by European Union for wine, must or grape juice (Regulation CE N. 123/2005). An analytical method based on immunoaffinity column (IAC) for clean-up and liquid chromatography with fluorescence detection (LC-FLD) was used to determine the occurrence of OTA in wines. Detection limit (LOD) and quantification Limit (LOQ) were 7.18 pg/ml and 9.31 pg/ml based on statistical method (IUPAC). Average recoveries of OTA from wine samples spiked at levels from 0.1 to 10 ng/ml ranged from 90.8% to 92.4%, with relative standard deviations (RSDs) between 2.64 and 2.71%. Repeatability limit was 8.73 pg/ml for samples spiked with 0.1 ng/ml of OTA. Ninety-one Denomination of Controlled Origin (DOC) wines were analysed, including 41 Barbera (red), 38 Dolcetto (red), and 16 white wines, such as Erbaluce, Cortese and Roero Arneis. The study focused on wines commercialized in Italian supermarkets and wine shops. The white wines resulted, as expected, less contaminated than the red ones. Wines produced after vintage 2003, a season particularly conducive to the growth of A. carbonorius, contained higher levels of OTA than the wines produced in 2004. The samples, resulting positive, contained a concentration of OTA highly inferior to the threshold limits introduced by the European Union. The sample of the highest level of OTA was a Dolcetto produced in 2004, with 1.10 ng/ml of mycotoxin.