OXIDATIVE DEGRADATION AND DETOXIFICATION OF MYCOTOXINS USING A NOVEL SOURCE OF OZONE

Abstract 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 μM) 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 (FB 1 ), ochratoxin A (OA), patulin, secalonic acid D (SAD) and zearalenone IZEN) 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, FB 1 (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 FB 1 . Importantly, degradation of FB 1 did not correlate with detoxification, since FB 1 solutions treated with O 3 were still positive in two bioassay systems.