M. Lopez et al., Sensitization of thermally injured spores of Bacillus stearothermophilus to sodium benzoate and potassium sorbate, LETT APPL M, 27(6), 1998, pp. 331-335
The effects of sodium benzoate and potassium sorbate added Co the recovery
medium, at different pH values (6.5, 6.0 and 5.0), on the recovery rates an
d heat resistance of Bacillus stearothermophilus spores (ATCC 12980, 7953,
15951 and 15952) were investigated. Heated spores of strains 12980 and 7953
were inhibited by sorbate concentrations over 0.05%. Potassium sorbate at
concentrations as low as 0.025%, and sodium benzoate at 0.1%, were very eff
ective inhibitory agents for heat-damaged spores. Their effectiveness alway
s increased at pH 5.0, at which no growth occurred, with sodium benzoate fu
r strains 7953, 15951 and 15952, and with potassium sorbate for strains 159
51 and 15952. Decimal reduction times, whenever recovery was possible, were
not significantly (P > 0.05) affected. None of these compounds modified th
e z-values obtained for the spores of the four strains, which had a mean va
lue of 7.53 +/- 0.28.