Toxicological studies on Lactose Oxidase from Microdochium nivale expressed in Fusarium venenatum

A new carbohydrate oxidase, Lactose Oxidase, with high specificity of oxidizing the disaccharide lactose to lactobionic acid has been found. This enzyme opens up for a variety of applications. A programme of toxicological studies was conducted to establish the safety of Lactose Oxidase to be used as a processing aid in the food industry. The enzyme used in this study was produced by a submerged fermentation of Fusarium venenatum and contained a gene code from Microdochium nivale. Oral administration to rats of up to 10 mL/kg bodyweight (bw)/day (equivalent to a total organic solids dosage of 900 mg/kg bw/day or a Lactose Oxidase dosage of 344 LOXU/kg bw/day) for 13 weeks did not cause any adverse effect. Lactose Oxidase was not found to be mutagenic in the bacterial reverse mutation assay, nor did it cause chromosomal aberrations in cultured human lymphocytes. The maximum recommended dosage of Lactose Oxidase is 50 LOXU/kg liquid whey protein concentrate. The safety margin for exposure is estimated to be at least 6.2 x 10(4) for daily diary product consumption. In conclusion Lactose Oxidase can be considered as safe for use in the food industry.