Oxidative degradation and detoxification of mycotoxins using a novel source of ozone

Practical methods to degrade mycotoxins using ozone gas (O-3) have been limited due to low O-3 production capabilities of conventional systems and their associated costs. Recent advances in electrochemistry (i.e. proton-exchange membrane and electrolysis technologies) have made available a novel and continuous source of O-3 gas up to 20% by weight. It is possible that the rapid delivery of high concentrations of O-3 will result in mycotoxin degradation in contaminated grains-with minimal destruction of nutrients. The major objectives of this study were to investigate the degradation and detoxification of common mycotoxins in the presence of high concentrations of O-3 In this study, aqueous equimolar (32 mu M) solutions of aflatoxins B-1 (AfB(1)), B-2 (AfB(2)), G(1) (AfG(1)), G(2) (AfG(2)), cyclopiazonic acid (CPA), fumonisin B-1 (FB1), ochratoxin A (OA), patulin, secalonic acid D (SAD) and zearalenone (ZEN) were treated with 2, 10 and/or 20 weight% O-3 over a period of 5.0 min and analysed by HPLC. Results indicated that AfB(1) and AfG(1) were rapidly degraded using 2% O-3, while AfB(2) and AfG(2) were more resistant to oxidation and required higher levels of O-3 (20%) for rapid degradation. In other studies, patulin, CPA, OA, SAD and ZEN were degraded at 15 sec, with no by-products detectable by HPLC. Additionally, the toxicity of these compounds (measured by a mycotoxin-sensitive bioassay) was significantly decreased following treatment with O-3 for 15 sec. In another study, FB1 (following reaction with O-3) was rapidly degraded at 15 sec, with the formation of new products. One of these appeared to be a 3-keto derivative of FB1. Importantly, degradation of FB1 did not correlate with detoxification, since FB1 solutions treated with O-3 were still positive in two bioassay systems. (C) 1997 Elsevier Science Ltd.