欧盟评估一种α-环糊精葡萄糖基转移酶的安全性

 

　　据了解，这种食品酶是由Wacker Chemie GmbH公司用转基因大肠肝菌（Escherichia coli ）菌株WCM105xpCM703生产的。由于缺乏关于这种α-环糊精葡萄糖基转移酶与已知过敏原的序列同源性的信息，专家小组无法完成对这种食物酶过敏原性的评估。因此该食品酶不能被认为是安全的。部分原文报道如下：

 

　　The food enzyme α‐cyclodextrin glucanotransferase ((1→4)‐α‐d‐glucan 4‐α‐d‐[(1→4)‐α‐d‐glucano]‐transferase; EC 2.4.1.19) is produced with a genetically modified Escherichia coli strain WCM105xpCM703 by Wacker Chemie GmbH. The production strain harbours a self‐replicating multicopy plasmid which contains genes conferring resistance to two highly important antimicrobials for human and veterinary medicine. The food enzyme is free from viable cells of the production organism, but not of its recombinant DNA. Therefore, the food enzyme poses a risk of promoting the spread of antimicrobial resistance genes. It is intended to be used in starch processing for the production of α‐cyclodextrin. Residual amounts of total organic solids (TOS) are removed by the purification steps applied during the production of α‐cyclodextrin; consequently, dietary exposure was not calculated. Genotoxicity tests, although not raising a safety concern, did not comply with the EFSA guideline. The systemic toxicity was assessed by means of a repeated dose 90‐day oral toxicity study in rats. The study was not supplied as a full report. The Panel identified the highest dose tested as the No Observed Adverse Effect Level, which according to the authors of the study corresponds to 260 mg TOS/kg body weight per day. In the absence of information about the sequence homology of this α‐cyclodextrin glucanotransferase with known allergens, the Panel could not complete the assessment on the allergenicity of the food enzyme. The Panel concludes that the food enzyme α‐cyclodextrin glucanotransferase produced with the genetically modified E. coli strain WCM105xpCM703 cannot be considered safe.