Mechanisms of heat and acid resistance in Escherichia coli O157:H7 and Listeria monocytogenes.

摘要

The influence of acid habituation and cell manipulations such as centrifuging and washing on heat and acid tolerances were evaluated for two strains of Escherichia coli O157:H7. Fatty acid profiles and internal pH of the cells were evaluated. O157:H7 grown in media supplemented with dextrose resulted in lower pH of the medium after 18 h at 35;The role of heat shock and cellular fatty acid composition in the elevation of heat resistance of O157:H7 was studied. Fatty acid composition of the cells was manipulated by supplementing the growth medium with fatty acids. Production of the heat shock protein GroEL was determined in all of six incubation treatments. Heat resistance (D;The role of heat shock and cellular fatty acid composition in the elevation of heat resistance of Listeria monocytogenes Scott A was studied. Four incubation treatments were evaluated. Heat shock of cells grown at 35