Graduate Institute of Food Science and Technology, National Taiwan University, Taipei, Taiwan.
Int J Food Microbiol. 2010 Dec 15;144(2):280-4. doi: 10.1016/j.ijfoodmicro.2010.10.006. Epub 2010 Oct 14.
Cronobacter spp., formerly Enterobacter sakazakii, are considered emerging opportunistic pathogens and the etiological agent of life-threatening bacterial infections in infants. In the present study, C. sakazakii BCRC 13988 was first subjected to sub-lethal heat treatment at 47°C for 15min. Survival rates of the heat-shocked and non-shocked C. sakazakii cells in phosphate buffer solution (PBS, pH 4.0) containing organic acids (e.g. acetic, propionic, citric, lactic or tartaric acid), simulated gastric juice (pH 2.0-4.0), and bile solution (0.5 and 2.0%) were examined. Results revealed that sub-lethal heat treatment enhanced the test organism's tolerance to organic acids, although the extent of increased acid tolerance varied with the organic acid examined. Compared with the control cells, heat-shocked C. sakazakii cells after 120-min of exposure, exhibited the largest increase in tolerance in the lactic acid-containing PBS. Furthermore, although heat shock did not affect the behavior of C. sakazakii in bile solution, it increased the test organism's survival when exposed to simulated gastric juice with a pH of 3.0-4.0.
阪崎克罗诺杆菌（Cronobacter spp.），以前被称为阪崎肠杆菌，被认为是新兴的机会致病菌，也是导致婴儿致命细菌感染的病原体。在本研究中，首次对阪崎克罗诺杆菌 BCRC 13988 进行了亚致死热处理，在 47°C 下处理 15min。在含有有机酸（如乙酸、丙酸、柠檬酸、乳酸或酒石酸）、模拟胃液（pH 2.0-4.0）和胆汁溶液（0.5%和 2.0%）的磷酸盐缓冲溶液（PBS，pH 4.0）中，分别检测了经亚致死热处理和未经热处理的阪崎克罗诺杆菌细胞的存活率。结果表明，亚致死热处理增强了受试菌对有机酸的耐受性，尽管有机酸的耐受性增加程度因所检测的有机酸而异。与对照细胞相比，在暴露于含乳酸的 PBS 120min 后，经热休克处理的阪崎克罗诺杆菌细胞的耐酸能力显著提高。此外，尽管热休克对胆汁溶液中阪崎克罗诺杆菌的行为没有影响，但它增加了受试菌在 pH 值为 3.0-4.0 的模拟胃液中的存活率。
