Safety evaluation of the use of the non-genetically modified Hamamotoa singularis strain YIT 10047 as a source of β-galactosidase

Abstract

This assessment addresses the enzyme β-galactosidase which is not separated from the yeast cells used for its production. The β-galactosidase (β-D-galactoside galactohydrolase, EC 3.2.1.23) is produced with the non-genetically modified Hamamotoa singularis (formerly Sporobolomyces singularis) strain YIT 10047 by Yakult Pharmaceutical Industry Co., Ltd. The yeast cell suspension contains both live and dead yeast cells. It is intended to be used in the production of galacto-oligosaccharides (GOS). The final GOS products are free of viable cells of the H. singularis. Dietary exposure to the food enzyme total organic solids (TOS) was estimated to be up to 0.683 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests of the cell suspension did not indicate 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 of 296.25 mg TOS/kg bw per day, the highest dose tested. This results in a margin of exposure above 434. A search for the similarity of the amino acid sequence of the β-galactosidase to known allergens was made and no matches were found. The Panel considered that, under the intended conditions of use, the risk of allergic reactions by dietary exposure cannot be excluded, but the likelihood for this to occur is low. Based on the data provided, the Panel concluded that this yeast suspension used as a source of β-galactosidase does not give rise to safety concerns under the intended conditions of use.