Safety evaluation of a hexose oxidase expressed in Hansenula polymorpha

A programme of studies was conducted to establish the safety of hexose oxidase (HOX) from Chondrus crispus expressed in the yeast Hansenula polymorpha to be used as a processing aid in the food industry. Rat feeding studies were conducted to assess acute and subchronic oral toxicity. In addition, the potential of the enzyme to cause mutagenicity and chromosomal aberrations was assessed in microbial and tissue culture in vitro studies. Acute and subchronic oral toxicity was not detected at the highest dosage recommended by OECD guidelines. There was no evidence of mutagenic potential or chromosomal aberrations. The no-observed-adverse-effect level (NOAEL) derived from the 13-week study was 5000 units/kg body weight/day. In conclusion it can be considered a safe processing aid for use in the food industry.