Cebrián G, Sagarzazu N, Pagán R, Condón S, Mañas P
Tecnología de los Alimentos, Facultad de Veterinaria de Zaragoza, Universidad de Zaragoza, C/ Miguel Servet, 177, 50013, Zaragoza, Spain.
Int J Food Microbiol. 2007 Sep 30;118(3):304-11. doi: 10.1016/j.ijfoodmicro.2007.07.051. Epub 2007 Aug 6.
The survival of four enterotoxigenic strains of Staphylococcus aureus (with different pigment content) to heat and to pulsed electric fields (PEF) treatments, and the increase in resistance to both processing stresses associated with entrance into stationary phase was examined. Survival curves to heat (58 degrees C) and to PEF (26 kV/cm) of cells in the stationary and in the exponential phase of growth were obtained. Whereas a wide variation in resistance to heat treatments was detected amongst the four strains, with decimal reduction time values at 58 degrees C (D(58 degrees C)) ranging from 0.93 to 0.20 min, the resistance to PEF was very similar. The occurrence of a higher tolerance to heat in stationary phase was coincident with a higher content in carotenoid pigmentation in S. aureus colonies. However, cells of the most heat resistant (pigmented) and the most heat sensitive (non-pigmented) strains in the mid-exponential phase of growth showed similar resistance to heat and to PEF. Therefore the increase in thermotolerance upon entrance into stationary phase of growth was more marked for the pigmented strains. Recovery in anaerobic conditions particularly enhanced survival to heat treatments in a non-pigmented strain. Strain CECT 4630, which possess a deficient sigma B activity, showed low heat resistance, low pigmentation, and reduced increase in thermotolerance in stationary phase. These results indicate that the magnitude of the development of a higher heat resistance in S. aureus in stationary phase is positively related to the carotenoid content of the strain. The development of tolerance to pulsed electric field was less relevant and not linked to the carotenoid content.
研究了四株产肠毒素金黄色葡萄球菌（色素含量不同）对热和脉冲电场（PEF）处理的耐受性，以及进入稳定期后对这两种加工应激的抗性增加情况。获得了处于生长稳定期和指数期的细胞对热（58℃）和PEF（26 kV/cm）的存活曲线。虽然在这四株菌中检测到对热处理的抗性存在很大差异，58℃下的十进制减少时间值（D(58℃)）范围为0.93至0.20分钟，但对PEF的抗性非常相似。金黄色葡萄球菌菌落中类胡萝卜素色素含量较高与稳定期对热的耐受性较高同时出现。然而，在生长指数中期，最耐热（有色素）和最热敏（无色素）菌株的细胞对热和PEF的抗性相似。因此进入生长稳定期后色素菌株的耐热性增加更为明显。在厌氧条件下恢复尤其增强了无色素菌株对热处理的存活能力。具有缺陷的σB活性的CECT 4630菌株表现出低耐热性、低色素沉着以及稳定期耐热性增加减少。这些结果表明，金黄色葡萄球菌在稳定期更高耐热性的发展程度与菌株的类胡萝卜素含量呈正相关。对脉冲电场耐受性的发展相关性较小，且与类胡萝卜素含量无关。
