食品中赭曲霉毒素A的产生机制及污染防控策略

Production Mechanisms and Control Strategies of Ochratoxin A in Food

赭曲霉毒素A(ochratoxin A,OTA)主要是由曲霉属(Aspergillus)和青霉属(Penicillium)真菌产生的有毒次级代谢产物,具有肾毒性、肝毒性、致畸性、神经毒性以及潜在致癌性,是世界范围内重点关注的真菌毒素之一。当前关于OTA产毒菌的分类、OTA合成途径及调控机制仍存在争议,制约了食品中OTA污染的高效精准控制。对曲霉属和青霉属中主要OTA产毒菌进行了系统梳理,特别是基于基因组比较数据将一度被认为是主要产毒菌的A.ochraceus中的部分菌株重新鉴定为A.westerdijkiae,介绍了主要产毒菌的产毒能力;系统介绍了OTA生物合成基因簇及关键合成与调控基因,特别是近年发现的新基因——环化酶otaY基因,其可能参与催化OTA生物合成途径初始步骤中的聚酮环化反应,基于最新研究结果进一步完善了OTA生物合成途径;针对食品生产不同环节,介绍了生物、物理和化学防控脱毒策略,重点介绍了针对产毒菌的生物防治方法,针对OTA毒素的生物降解菌及脱毒酶,并比较了不同方法的优缺点。最后,提出了食品OTA污染控制应基于“全链条控制”和“源头防控”的思路,保障食品安全、粮食安全和人民生命健康;分析了生物防治和生物脱毒技术的优缺点,指出绿色、安全的生物防控策略具有广阔的应用前景,是未来研究的重点方向。

Ochratoxin A(OTA)is a toxic secondary metabolite mainly produced by fungi from the genera Aspergillus and Penicillium,and it has nephrotoxicity,hepatotoxicity,teratogenicity,neurotoxicity,potential carcinogenicity,and is one of the mycotoxins of great concern worldwide.However,the classification of OTA-producing fungi,OTA biosynthetic pathway and regulatory mechanism are still controversial,which restricts the efficient and accurate control of OTA contamination in food.Therefore,the main OTA-producing fungi in Aspergillus and Penicillium were systematically sorted out and classified.In particular,some strains of A.ochraceus once considered as the main toxigenic fungi were re-identified as A.westerdijkiae based on genomic comparison data,and the toxigenic ability of the main OTA-producing fungi was introduced.The OTA biosynthetic gene clusters,key biosynthetic and regulatory genes were systematically sorted out and introduced,especially the new gene,the cyclase otaY gene,which may be involved in catalyzing the polyketide cyclizing reaction in the initial step of OTA biosynthesis.Based on the latest research results,the OTA biosynthetic pathway was further improved.According to the different stages of food production,the biological,physical and chemical control and detoxification strategies of OTA-producing fungi were sorted out.The biocontrol methods against OTA-producing fungi,and the biodegradation bacteria and detoxification enzymes for OTA were introduced,and the advantages and disadvantages of different methods were compared and discussed.Finally,it was proposed that the control of OTA contamination in food should be based on the idea of“whole chain control”and“source prevention and control”to ensure food safety and people s life and health.The advantages and disadvantages of biological control and biological detoxification technology were discussed.It was pointed out that a green and safe biological control strategy had broad application prospects and was the key direction of future research.