Safety evaluation of the food enzyme isoamylase from a Dyella sp. strain

The food enzyme isoamylase (glycogen α-1,6-glucanohydrolase, EC 3.2.1.68) is produced with Dyella sp. by Hayashibara Co. Ltd. Whole genome sequence analysis of the production strain identified a sequence with high homology with a gene conferring resistance to an antimicrobial, which may confer cross-resistance to a critically important antimicrobial, as defined by the World Health Organisation. This is a concern, since DNA from the production strain was detected in the food enzyme. The isoamylase food enzyme is intended to be used in starch processing for the production of various starch hydrolysates. Since residual amounts of total organic solids are removed by the purification steps applied during the production of saccharides from starch, dietary exposure was not calculated. The batch used for toxicological testing was not sufficiently characterised; therefore, the toxicological data provided were not considered. 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 for this to occur is considered to be low. Overall, the Panel cannot conclude on the safety of the food enzyme isoamylase produced with Dyella sp.