Safety evaluation of the food enzyme β‐glucanase, xylanase and cellulase from Mycothermus thermophiloides (strain NZYM‐ST)
The food enzyme has three declared activities (endo‐1,3(4)‐β‐glucanase EC 126.96.36.199, endo‐1,4‐β‐xylanase EC 188.8.131.52 and cellulase (endo‐1,4‐β‐d‐glucanase EC 184.108.40.206)) and is produced with a non‐genetically modified Mycothermus thermophiloides strain by Novozymes A/S. It is intended to be used in baking and brewing processes. For the two intended uses, based on the maximum use levels recommended and individual data from the EFSA Comprehensive European Food Database, dietary exposure to the food enzyme–Total Organic Solids (TOS) was estimated to be up to 0.411 mg TOS/kg body weight (bw) per day. Genotoxicity tests did not raise a safety concern. Systemic toxicity was assessed by a repeated dose 90‐day oral toxicity study in rats. From this study, the Panel identified a no observed adverse effect level (NOAEL) of at least 620 mg TOS/kg bw per day, the highest dose tested. When the NOAEL is compared to the estimated dietary exposure, this results in a margin of exposure of at least 1,500. A search was made for similarity of the amino acid sequence of the declared activities with those of known allergens. Four matches were found with endo‐1,3(4)‐β‐glucanase to known respiratory allergens, two from dust mites and two Aspergillus fumigatus allergens. The Panel considered that an allergic reaction upon oral ingestion of enzymes produced by M. thermophiloides strain NZYM‐ST in individuals respiratory sensitised to these allergens cannot be excluded, but the likelihood is considered to be low. Overall, the Panel concluded that, under the intended conditions of use and based on the data provided, this food enzyme does not give rise to safety concerns.