Occurrence of Ochratoxin A in coffee beans, ground roasted coffee and soluble coffee and method validation

The purpose of this work was to determine the occurrence of Ochratoxin A (OTA) in coffee beans, ground roasted coffee and soluble coffee, which is imported by Argentina and manufactured in this country and also to perform a single laboratory validation for the analysis of OTA. Validation was done with certified reference material and with spiked samples. Certified material showed 104% of toxin recovery in the case of roasted coffee and 100% for green coffee. Spiked samples with levels from 1.98 to 10.18 μg/kg for soluble coffee had an average recovery rate of 79.4%. The limits of detection and quantification in coffee were 0.02 μg/kg and 0.05 μg/kg respectively. A good correlation (r = 0.9989) was found for this method. Fifty one samples were investigated to determine the presence of OTA, extracted by Ochraprep® immunoaffinity columns for cleaning up and analysed by high performance liquid chromatography (HPLC). The results showed that a high percentage (69%) of the coffee was contaminated with OTA at different levels. The median obtained for green coffee was 2.7 μg/kg, for ground roasted coffee was 0.24 μg/kg and 0.43 μg/kg for soluble coffee. A possible exposure assessment was evaluated.