Ochratoxin A in wines-assessing global uncertainty associated with the results Original Research Article

Ochratoxin A (OTA) is a mycotoxin (potentially carcinogenic secondary metabolite derived from fungal contamination), produced by some Aspergillus and Penicillium strains. Although present and legislated in different food sources in the human diet, the regulation for wine intake is still under discussion. The Office International de la Vigne et du Vin (OIV) recommended maximum levels in wine of 2 μg l−1. Some reports refer to OTA contamination in wines up to 15 μg l−1 and a special incidence in red wines from the southern regions of Europe and the north of Africa, but the majority of the data available are below 1 μg l−1. When working at such low concentrations, the problem of the uncertainty of the results becomes decisive towards the implementation of legal limits. In order to assess the global uncertainty associated with OTA determination in wines and widen the data set and knowledge of the situation in Portugal, 340 wines were analysed (189 Port Wine, 85 Vinho Verde and 66 wines from other regions in the country) by a high performance liquid chromatography (HPLC)–fluorescence detection (FD) method using immunoaffinity columns for clean up. OTA was detected in 69 wines by the method used, but in concentrations below 0.5 μg l−1, except for two which showed levels up to a maximum of 2.1 μg l−1. However, the global uncertainty for OTA is close to 37% for concentrations above 0.5 μg l−1, and therefore, such value can be below or exceed the OIV limit. In the vicinity of the limit of detection, 0.084 μg l−1, the global uncertainty rises exponentially to a maximum of about 70%. This can be an obstacle when discussing safety intake limits. Ethanol and glucose content did not interfere in the clean up of OTA by immunoaffinity columns.