Temperature alters the structure of membrane lipids and pulsed electric field (PEF) resistance of Salmonella typhimurium

Abstract

The effect of culture temperature on the conformation of membrane lipid of Salmonella typhimurium as well as their pulsed electric field (PEF) resistance was investigated. Results revealed that S. typhimurium cells cultured at relatively lower temperature (10 and 25 °C) were more easily inactivated by PEF treatment than those cultured at relatively higher temperature (37 and 45 °C). Using a Weibull model, it was determined that the PEF treatment time to inactivate 90% S. typhimurium cells cultured at 45 °C was almost fourfold compared to those cultured at 10 °C. Results of micro-Raman spectroscopy indicated that as the culture temperature increased, the order degree of C–C and lateral packing order of membrane lipid chain also increased, resulting in a drop in the membrane fluidity. These results are important in considering the use of heat and PEF to inactivate microbe contaminants in food.