Determination of ochratoxin A in domestic and imported beers in Italy by immunoaffinity clean-up and liquid chromatography

A method first developed to quantify ochratoxin A in wine has been applied to the analysis of domestic and imported beers in Italy. The method uses co mmercial immunoaffinity columns for clean-up and high-performance liquid ch romatography for quantification of the toxin. Beer was degassed, then dilut ed with a polyethylene glycol-sodium hydrogencarbonate solution and applied to an OchraTest immunoaffinity column. Ochratoxin A was eluted from the im munoaffinity column with methanol and quantified by reversed-phase HPLC wit h fluorometric detector. Average recoveries of ochratoxin A from blank beer spiked at levels from 0.04 to 1.0 ng/ml ranged from 93.8% to 100.4%, with relative standard deviations between 3.3% and 5.7%. The detection limit was 0.01 ng/ml based on a signal-to-noise ratio of 3:1. The analysis of 61 sam ples of domestic (10) and imported (51) beers showed ochratoxin A levels ra nging from <0.01 to 0.135 ng/ml with an incidence of contamination of 50% a nd no substantial difference between strong and pale beers. (C) 2000 Elsevi er Science B.V. All rights reserved.