Teagasc, Moorepark Food Research Centre, Fermoy, Ireland.
Foodborne Pathog Dis. 2011 Sep;8(9):975-81. doi: 10.1089/fpd.2010.0819. Epub 2011 May 4.
Adaptation to sublethal stress can confer increased survival capability on foodborne pathogens. In this article, we report on the adaptive response of Cronobacter spp. to heat and compare the survival of heat adapted to unadapted Cronobacter spp. Five different isolates, representing at least three different Cronobacter spp., were adapted at 46°C for 30 min and subjected to a lethal stress at 52°C. All showed increased survival upon adaptation. Survival was greater in milk-grown cells, but broth-grown cells showed a higher degree of adaptation. The survival potential acquired following adaptation was not transferred to survival in a dry environment or to survival during reconstitution of artificially contaminated milk powder by conventional or microwave heat. The ratio of membrane unsaturated to saturated fatty acids decreased, possibly resulting in a more rigid membrane in adapted cells. Heat-adapted cells showed increased survival potential to lethal heat stress, but not to dry stress. Alterations in the ratio of fatty acids in the membrane may explain this adaptation.
适应亚致死应激可以赋予食源性病原体更高的生存能力。在本文中，我们报告了克罗诺杆菌属对热的适应反应，并比较了热适应和未适应的克罗诺杆菌属的生存能力。五个不同的分离株，至少代表三种不同的克罗诺杆菌属，在 46°C 下适应 30 分钟，然后在 52°C 下进行致死应激。所有分离株在适应后均表现出更高的存活率。在牛奶中生长的细胞的存活率更高，但在肉汤中生长的细胞的适应程度更高。适应后获得的生存能力不能转移到干燥环境中的生存能力，也不能转移到通过传统或微波加热对人工污染奶粉进行复水时的生存能力。膜不饱和脂肪酸与饱和脂肪酸的比例降低，可能导致适应细胞的膜更刚性。热适应细胞对致死热应激的生存能力增加，但对干燥应激的生存能力没有增加。膜中脂肪酸比例的改变可能解释了这种适应。
