Staphylococcus aureus 의 sublethal heating 후 NaCl 농도에 따른 회복 정도 비교

Abstract

The viability of Staphylococcus aureus, a significant cause of food poisoning in Korea, on TSA plates was determined after sublethal heating treatments and NaCl treatments. In addition, recovery levels of sublethally injured cells on TSA plates containing different concentrations of NaCl (TSAS) were investigated. The viability decreased significantly with increasing degree of sublethal heating treatments, but increases in NaCl treatment concentrations from 0 to 6% had little effect on the viability. After being sublethally treated at 55oC for 30 min, bacterial populations were reduced by 7.91, 7.97 and 7.99 log CFU/mL on 2, 4 and 6% TSAS, respectively. After being sublethally treated at 60oC for 30 min, bacterial populations were reduced by 6.46, 6.47 and 6.48 log CFU/mL on 2, 4 and 6% TSAS, respectively. Decimal reduction times (D-value) decreased with increasing NaCl treatment concentrations after sublethal heating at 55 and 60oC. These data imply that the S. aureus cells sublethally injured by insufficient heating processes had a lower recovery rate with increasing NaCl concentrations in the recovery media.