Abstract
Increasing concentrations (2, 4 and 8% w/v) of sodium chloride in the heating medium progressively reduced the heat resistance of spores of Bacillus stearothermophilus. Storage at 4° in water or in sodium chloride solutions had little effect on viable counts of unheated spores, but with the increase in sodium chloride concentration there was a reduction in the heat activation effect and a small decrease in heat resistance of the spores. Increasing the severity of heat treatment rendered spores increasingly sensitive to sodium chloride in the plating medium.