Evaluation of recovery media for heated spores of <i>Bacillus stearothermophilus</i>

Abstract

The effects of different media, additives, pH and incubation temperatures were studied on the recovery of heat‐treated spores of Bacillus stearothermophilus. Raising the pH from 6.5 to 7.3 increased the shoulder and decreased the subsequent exponential rate of inactivation with some of the media. Addition of starch or charcoal caused a significant increase in the level of recovery. No significant differences were observed by using two incubation temperatures (50° or 60°C). Yeast‐peptone‐tryptone‐dextrose medium plus starch was found to be the best of the media used.