Determining the Safety of Maltogenic Amylase Produced by rDNA Technology.

A maltogenic amylase produced by a genetically engineered Bacillus subtilis was studied to evaluate its safety in the food industry. First, the safety of the component parts used in the cloning process, i.e. the host organism ( B. subtilis ), the donor organism ( Bacillus stearothermophilus ) and the construction process, were evaluated. This evaluation indicated that the final construct should be regarded as a safe source for maltogenic amylase when manufactured according to current Good Manufacturing Practices. Additional experimental safety testing was carried out to confirm this conclusion. In a 13-week oral toxicity study rats tolerated the maltogenic amylase at dietary levels of 5% without toxicologically significant adverse reaction. Lack of mutagenic potential was confirmed in bacterial mutagenic as-says with Salmonella typhimurium and in an in vivo cytogenetic study in rat bone marrow cells. In an acute inhalation study with 4 h of exposure to rats, no death occurred at the highest dose level, i.e, 1.59 mg/L. The test material was non-irritating to skin and did not product eye injury in rabbits. A skin sensitization study in guinea pigs was negative. Antibiotic activity tests indicated that the microorganism did not produce antibiotics. Results indicated that maltogenic amylase should be generally recognized as safe for use in production of maltose syrups, and confirmed the conclusion drawn from the safety evaluation of the component parts used in the cloning process.