THE OCCURRENCE OF OCHRATOXIN-A IN COFFEE

Ochratoxin A (OA) is a nephrotoxic and nephrocarcinogenic mycotoxin wh ich is predominantly produced by the two ubiquitous fungal genera, Asp ergillus and Penicillium. OA is found in foodstuffs, predominantly in cereals but also in coffee beans. Inconsistent results have been publi shed regarding the influence of roasting on the OA content in roasted beans and the transfer into the coffee brew. In the present study an H PLC method was used for the detection of OA in green and roasted coffe e beans as well as in the coffee brew. For qualitative confirmation an d quantification of low OA levels in roasted coffee beans and coffee b rew an additional clean-up step by immunoaffinity column was applied b efore HPLC analysis. In green coffee beans OA was detected in 13 out o f 25 commercial samples analysed (detection limit, 0.5 mu g OA/kg). Ro asting(250 degrees C, 150 sec) of naturally contaminated green beans o r beans inoculated with A, ochraceus resulted only in a small reductio n in the OA level. OA was also found to be eluted into the brew. Of 40 coffee brews prepared from commercially available samples OA was dete cted in 18 brews by HPLC and/or additional immunoaffinity column clean -up in the range of 0.4 to 7.8 mu g OA/kg equivalent ground coffee. Ou r preliminary results suggest, therefore, that regular coffee consumpt ion may contribute to exposure of humans to OA.