Inactivation of Escherichia coli and Lactobacillus plantarum in relation to membrane permeabilization due to rapid chilling followed by cold storage

• Published in: Archives of microbiology Vol. 192; no. 4; pp. 299 - 305
• Main Authors: Cao-Hoang, L, Dumont, F, Marechal, P. A, Gervais, P
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Berlin/Heidelberg : Springer-Verlag 01.04.2010; Springer-Verlag; Springer; Springer Nature B.V; Springer Verlag
• Subjects: Bacteriology; Biochemistry; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Cell Biology; Cell death; Cell Membrane Permeability; Chemical and Process Engineering; Cold storage; Cold Temperature; Cooling; E coli; Ecology; Engineering Sciences; Escherichia coli - physiology; Flow Cytometry; Fluorescent Dyes; Fundamental and applied biological sciences. Psychology; Inactivation; Iodides; Lactobacillus plantarum - physiology; Life Sciences; Low temperature; Membranes; Metabolism; Microbial Ecology; Microbial Viability; Microbiology; Microorganisms; Miscellaneous; Original Paper; Propidium; Temperature; France; Chilling rate; Membrane permeabilization; Cell viability; Cold shock; Lactic acid bacteria; Lactobacillus plantarum; Storage; Escherichia coli; Bacteria; Lactobacillaceae; Enterobacteriaceae
• ISSN: 0302-8933; 1432-072X
• DOI: 10.1007/s00203-010-0555-y

The relationship between membrane permeabilization and loss of viability by chilling depending on the chilling rate was investigated in two bacterial models: one Gram-positive bacterium, Lactobacillus plantarum, and one Gram-negative bacterium, Escherichia coli. Cells were cold shocked slowly (2°C/min) or rapidly (2,000°C/min) from physiological temperature to 0°C and maintained at this temperature for up to 1 week. Loss of membrane integrity was assessed by the uptake of the fluorescent dye propidium iodide (PI). Cell death was found to be strongly dependent on the rate of temperature downshift to 0°C. Prolonged incubation of cells after the chilling emphasized the effect of treatment on the cells, as the amount of cell death increased with the length of exposure to low temperature, particularly when cells were rapidly chilled. More than 5 and 3-log reductions in cell population were obtained with L. plantarum and E. coli after the rapid cold shock followed by 7-day storage, respectively. A correlation between cell inactivation and membrane permeabilization was demonstrated with both bacterial strains. Thus, loss of membrane integrity due to the chilling treatments was directly involved in the inactivation of vegetative bacterial cells.