Heat Shock Treatment Affects the Survival of Enterobacter sakazakii Subjected to Subsequent Lethal Conditions
Date Issued
2008
Date
2008
Author(s)
Chang, Chia-Hsiang
Abstract
Enterobacter sakazakii is an emerging opportunistic pathogen which has been associated with life-threatening cases in infants, with infant formulas been implicated as the mode of transmission. In the present study, E. sakazakii BCRC 13988, the type strain, was subjected to various heat shock treatments (42-48℃, 5-15 min). Their subsequent survival at 51 ℃ and leakage of intracellular materials were investigated. Additionally, survivals of heat-shocked E. sakazakii BCRC 13988 during subsequent exposure to various stress conditions, including high osmotic pressure (75% sorbitol), air drying, low temperature (3 and -20℃) and ethanol (15%), were also investigated.esults revealed that heat shock treatments increased the thermal tolerance of E. sakazakii BCRC 13988. Heating at 47℃ for 15 min, among the various heat shock treatments examined, was found to enhance the survival of test organism at 51℃ most profoundly. Electron micrograph showed that heat shock treatment caused the damage and disruption of the E. sakazakii BCRC 13988 cells. The extracellular 260 and 280 nm-absorbing materials increased as the temperature and the period of heat treatment were increased. Besides, the heat-shocked cells of test organism exhibited enhanced survival when they were exposure to high osmotic pressure, air drying, ethanol, refrigerated or frozen storage.
Subjects
heat shock
heat tolerance
Type
thesis
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