Occurrence of ochratoxin A in wine and grape juice marketed in Rio de Janeiro, Brazil

Abstract

Ochratoxin A (OA) is receiving attention world-wide because of the hazard it poses to human health. The aim was to test the distribution of OA in grape juice, pulps of frozen grapes, and national and imported table wine obtained from markets in Rio de Janeiro, Brazil. Analytical methodology using immunoaffinity column for OA extraction and clean-up with a final separation on a reversed-phase (C₁₈) column and fluorescence detection in high-performance liquid chromatography showed a detection limit of 21 ng l⁻¹. The mean recovery was 91% for red wines and 82% for white wines; while the mean recoveries for juices and pulps of frozen grapes were 91.6 and 88%, respectively. Of 64 samples of grape juice and frozen pulps, 25% were positive for OA, being the mean content of 37 ng l⁻¹ with a maximum concentration of 100 ng l⁻¹. In wines, the mean concentration detected in 80 samples analysed was 34.4 ng l⁻¹ with 28.75% of positive samples. Red wines showed the highest percentages and levels of contaminated samples: 38% and 37 ng l⁻¹, respectively. The white wine contained levels above 26 ng l⁻¹ in 17.75% of the analysed samples. The levels of contamination detected in red wine sold in Río de Janeiro were not enough to surpass the virtually safe dose established as 5 n g kg⁻¹ body weight of daily intake.

Keywords:

• ochratoxin A
• grape juice
• pulps of frozen grapes
• wine grapes

Acknowledgements

The authors are grateful to the Fundação de Apoio a Pesquisa da Universidade Rural (FAPUR), Solcamp-Sanidade Animal and VICAM (Watertown, MA, USA), which supported the study through grants and materials.