Ochratoxin A and its metabolite ochratoxin alpha in urine and assessment of the exposure of inhabitants of Lleida, Spain

Ochratoxin A (OTA) as well as its metabolite ochratoxin α (OTα) were detected in human urine in order to assess the exposure to OTA of a group of 72 adult inhabitants of the city of Lleida (Spain). Urine samples were enzymatically treated; OTA and OTα were separated by liquid-liquid extraction, and detected by HPLC-fluorescence. Exposure to OTA was also evaluated by the estimation of its daily intake from food contamination data from the literature and from food consumption data provided by the participants, who filled in a food frequency questionnaire (FFQ) and a three-day food consumption record (3DR). OTA occurrence (12.5%, limit of detection = 0.034 ng/mL) was lower than OTα occurrence (61.1%, limit of detection = 0.023 ng/mL). The range of concentrations was 0.057-0.562 ng/mL and 0.056-2.894 ng/mL for OTA and for OTα, respectively. It could be observed for positive samples that the FFQ data were related to the OTA concentration in urine, whereas the 3DR data were related to the OTα levels in urine. The OTA estimated daily intake of the participants was lower than 30% of the latest provisional tolerable daily intake of 14 ng/kg body weight/day in the worst cases of exposure.