Levels of ochratoxin A in serum from urban and rural Portuguese populations and estimation of exposure degree

Urban and rural population exposure to ochratoxin A (OTA) in central zone of Portugal was investigated in three places: Coimbra, Verride and Ereira. The analytical method proposed for the determination of ochratoxin A involved extraction with chloroform-orthopliosphoric acid, cleanup through an irnmunoaffinity column (IAC), high performance liquid chromatography (HPLC) with spectrofluorimetric detection (FD) for separation and identification of ochratoxin A, and confirmation with HPLC-FD after OTA methylation in serum. The limit of quantification of the proposed method was 0.1 mu g/L for serum and 0.05 mu g/L for blood. OTA recoveries in serum ranged from 70.3% to 115.3% for levels at 0.25 mu g/L and 0.5 mu g/L, respectively, with a within-day RSD between 8.0% and 16.2%. Ochratoxin A serum levels were evaluated in an hundred and four donors from Coimbra city, Verride, and Ereira. The study revealed a frequency of detection of 100%. The ratio of ochratoxin A level in serum to whole blood was 2.0 +/- 0.7. The overall concentrations range from 0.25 to 2.49 mu g/L, 0.14 to 1.91 mu g/L, and 0. 19 to 0.96 mu g/L, for samples of Verride, Ereira, and Coimbra, respectively. The mean concentration and standard deviation were 0.78 +/- 0.53 mu g/L, 0.44 +/- 0.31 mu g/L, and 0.42 +/- 0.18 mu g/L for the same samples. A significant difference was found in Verride population (P-value = 0.000). Levels of OTA are clearly higher in males from rural areas than in females. For all samples, a significant difference was found in Verride male population (P-value = 0.014). (c) 2007 Elsevier Ltd. All rights reserved.