Inactivation and occurrence of sublethal injury of Salmonella Typhimurium under mild heat stress in broth
Inactivation and occurrence of sublethal injury of Salmonella Typhimurium under mild heat stress in broth
复制标题
肉汤轻度热应激下鼠伤寒沙门氏菌的灭活及亚致死损伤的发生
DOI：
10.1007/s00003-012-0763-2
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发表时间：
2012-06-01
影响因子：
--
通讯作者：
Shi, Xianming
中科院分区：
文献类型：
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作者：
Suo, Biao;Shi, Chunlei;Shi, Xianming
食品的热加工仍然是用于提高微生物安全性的标准商业方法。评价了鼠伤寒沙门氏菌菌株的细胞特性（如生长期、细胞密度以及营养素和代谢物的可用性）对暴露于55 °C温和热处理时存活细胞减少3 Log10的影响。使用非选择性和选择性琼脂，它表明，在热应力下，鼠伤寒沙门氏菌遭受损伤的外和细胞质膜，从而导致细胞死亡。与静止期细胞相比，指数生长期细胞更容易受到热损伤，尤其是细胞质膜。热失活和损伤的发生随着细胞密度的增加而减少，并且随着细胞生长过程中产生的代谢产物的可用性的增加而减少，但与培养液中的营养成分没有明显的相关性。结果揭示了细胞生长阶段、细胞密度和代谢产物利用率在鼠伤寒沙门氏菌耐热性中的重要性。因此，这些因素应该得到很好的考虑时，模型的构建和用于预测热效应的病原体的生存。此外，我们的数据表明，当选择性培养基用于检测亚致死损伤细胞时，应予以注意。
Thermal processing of food products continues to be the standard commercial method used for enhancing microbiological safety. The influence of cell characteristics of Salmonella Typhimurium strains, such as growth phase, cell density, and the availability of nutrients and metabolites was evaluated regarding a 3 Log10 reduction of surviving cells when exposed to a mild heat treatment of 55 °C. Using nonselective and selective agars it was revealed that under thermal stress Salmonella Typhimurium suffered from injuries on both outer and cytoplasmic membrane, which consequently led to cell death. Compared to stationary cells, those in exponential growth phase were more prone to thermal injury, especially on the cytoplasmic membrane. Occurrence of thermal inactivation and injury decreased with the increase of cell density, and with the increased availability of metabolites produced during cell growth, but showed no apparent correlation with nutrients in the culture broth. The results enlighten the importance of cell growth phase, cell density and metabolite availability in Salmonella Typhimurium thermal resistance. Consequently these factors should be well considered when models are constructed and used to predict thermal effects on the survival of the pathogen. Moreover, our data show that attention should be paid when selective media are used to detect sublethally injured cells.