Heat resistance, membrane fluidity and sublethal damage in Staphylococcus aureus cells grown at different temperatures
Resumen: In this work the influence of growth temperature (10–42¿°C) on Staphylococcus aureus heat resistance was studied, and its relationship with the ability of cells to repair sublethal damages and with membrane fluidity was evaluated. Non-linear, convex from above survival curves were obtained, and therefore a special case of the Baranyi model was used to fit them. For exponential phase cells, heat resistance did not change with growth temperature in the range between 10 and 37¿°C, but cells grown at 42¿°C were significantly more resistant, showing D58 and shoulder length (sl58) values 2.5 and 4 times greater than the others, respectively. For stationary growth phase cells, an increase in growth temperature above 20¿°C resulted in an increase in D58 values, and cells grown at 42¿°C also displayed the highest D58 and sl58 values. The increased heat resistance at 58¿°C of stationary growth phase cells grown at higher temperatures was coincident with the appearance of a higher proportion of sublethally damaged cells capable of recovery and outgrowth in non-selective medium. Membrane fluidity was measured at treatment temperatures, and it was observed that those cells with more rigid membranes displayed greater heat resistance (Pearson coefficient¿=¿0.969***). Additionally, S. aureus cells whose membrane was fluidized through exposure to benzyl alcohol were notably sensitized against the action of heat, in a concentration-dependent manner. Results obtained in this research indicate that membrane physical state could be an important factor determining the survival capacity of bacterial cells to a heat treatment.
Idioma: Inglés
DOI: 10.1016/j.ijfoodmicro.2018.09.002
Año: 2019
Publicado en: INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY 289 (2019), 49-56
ISSN: 0168-1605

Factor impacto SCIMAGO:

Financiación: info:eu-repo/grantAgreement/ES/MINECO/AGL2015-69565-P
Tipo y forma: Article (PostPrint)
Área (Departamento): Área Tecnología de Alimentos (Dpto. Produc.Animal Cienc.Ali.)

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