Silano Vittorio, Barat Baviera José Manuel, Bolognesi Claudia, Brüschweiler Beat Johannes, Cocconcelli Pier Sandro, Crebelli Riccardo, Gott David Michael, Grob Konrad, Lampi Evgenia, Mortensen Alicja, Rivière Gilles, Steffensen Inger-Lise, Tlustos Christina, Van Loveren Henk, Vernis Laurence, Zorn Holger, Herman Lieve, Jany Klaus-Dieter, Aguilera Jaime, Aguilera-Gómez Margarita, Andryszkiewicz Magdalena, Arcella Davide, Gomes Ana, Kovalkovičová Natalia, Liu Yi, Chesson Andrew
EFSA J. 2019 Jan 11;17(1):e05550. doi: 10.2903/j.efsa.2019.5550. eCollection 2019 Jan.
The food enzyme is an endo-1,4-β-xylanase (4-β-d-xylan xylanohydrolase; EC 3.2.1.8) produced with the genetically modified strain XAS. Antibiotic resistance genes are present in the production organism on a self-replicative vector. The endo-1,4-β-xylanase is intended to be used in baking processes. Based on the maximum use levels, dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 0.014 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no-observed-adverse-effect level (NOAEL) of 55 mg TOS/kg bw per day that, compared with the estimated dietary exposure, results in a sufficiently high margin of exposure (MOE) (of at least 3,600). Similarity of the amino acid sequence to those of known allergens was searched and no match was found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions by dietary exposure cannot be excluded, but the likelihood to occur is considered to be low. Since the absence of viable cells in the food enzyme has not been adequately demonstrated, the Panel cannot conclude on the risks associated with the possible spread of a genetically modified bacterial strain carrying antimicrobial resistance determinants.
这种食品酶是一种内切-1,4-β-木聚糖酶（4-β-D-木聚糖木聚糖水解酶；EC 3.2.1.8），由转基因菌株XAS生产。生产生物体中存在于自我复制载体上的抗生素抗性基因。该内切-1,4-β-木聚糖酶拟用于烘焙过程。根据最大使用量，估计欧洲人群通过饮食接触该食品酶的总有机固体（TOS）最高可达每天0.014毫克TOS/千克体重（bw）。遗传毒性试验未引发安全担忧。通过对大鼠进行的重复剂量90天口服毒性研究评估了全身毒性。专家小组确定的无观察到不良反应水平（NOAEL）为每天55毫克TOS/千克bw，与估计的饮食接触量相比，产生了足够高的接触边际（MOE）（至少为3600）。搜索了该氨基酸序列与已知过敏原的氨基酸序列的相似性，未发现匹配。专家小组认为，在预期的使用条件下，不能排除通过饮食接触引起过敏致敏和激发反应的风险，但认为发生的可能性较低。由于尚未充分证明食品酶中不存在活细胞，专家小组无法就与携带抗微生物抗性决定因素的转基因细菌菌株可能传播相关的风险得出结论。
