Cebrián G, Sagarzazu N, Pagán R, Condón S, Mañas P
Tecnología de los Alimentos, Facultad de Veterinaria de Zaragoza, Universidad de Zaragoza, Zaragoza, Spain.
J Appl Microbiol. 2008 Jul;105(1):271-8. doi: 10.1111/j.1365-2672.2008.03745.x. Epub 2008 Feb 13.
To study the influence of growth temperature on the resistance of Escherichia coli to three agents of different nature: heat, pulsed electric field (PEF) and hydrogen peroxide.
Escherichia coli cells were grown to stationary phase at 10 degrees C, 20 degrees C, 30 degrees C, 37 degrees C and 42 degrees C. Survival curves to a heat treatment at 57.5 degrees C, to a PEF treatment at 22 kV cm(-1) and to 40 mmol l(-1) hydrogen peroxide were obtained and fitted to a model based on the Weibull distribution to describe and compare the inactivation. Time to inactivate the first log cycle of the population at 57.5 degrees C of cells grown at 42 degrees C was sixfold higher than that corresponding to cells grown at 10 degrees C. On the contrary, cells grown at 10 degrees C and 20 degrees C were more resistant to PEF and hydrogen peroxide treatments.
The influence of growth temperature on bacterial resistance depends on the stress applied. Cells grown at higher temperatures were more heat resistant, but more sensitive to PEF and hydrogen peroxide.
Results obtained in this investigation help in understanding the physiology of bacterial resistance and the inactivation mechanisms of different technologies.
研究生长温度对大肠杆菌对三种不同性质的处理剂（热、脉冲电场（PEF）和过氧化氢）抗性的影响。
将大肠杆菌细胞分别在10℃、20℃、30℃、37℃和42℃培养至稳定期。获得了在57.5℃热处理、22 kV cm⁻¹脉冲电场处理以及40 mmol l⁻¹过氧化氢处理下的存活曲线，并将其拟合到基于韦布尔分布的模型中，以描述和比较失活情况。在57.5℃下使在42℃生长的细胞群体的第一个对数周期失活所需的时间比在10℃生长的细胞相应时间高六倍。相反，在10℃和20℃生长的细胞对脉冲电场和过氧化氢处理更具抗性。
生长温度对细菌抗性的影响取决于所施加的应激。在较高温度下生长的细胞更耐热，但对脉冲电场和过氧化氢更敏感。
本研究获得的结果有助于理解细菌抗性的生理学以及不同技术的失活机制。
