El-Kest Souzan E, Marth Elmer H
Department of Food Science and the Food Research Institute, University of Wisconsin-Madison, Madison, Wisconsin 53706.
J Food Prot. 1988 Aug;51(8):622-625. doi: 10.4315/0362-028X-51.8.622.
Listeria monocytogenes strain Scott-A was treated with 1 ppm available chlorine at different temperatures and pH values. Different strains of L. monocytogenes (California, Scott-A and V7) were also exposed to 1 ppm available chlorine at pH 7 and 25°C. The initial population of L. monocytogenes was 1 × 10 to 3.2 × 10 CFU/ml of sodium hypochlorite solution. Survival of L. monocytogenes was measured by surface-plating (on tryptose agar) samples taken at intervals of 30 s to 1 h of exposure to hypochlorite solution. Larger numbers of L. monocytogenes strain Scott-A survived at 25 than at 35°C. The smallest number was observed when cells were exposed to the hypochlorite solution at 5°C. The higher the pH values, in the range of 5 to 9, the greater were the numbers of survivors of L. monocytogenes strain Scott-A. Of the strains studied, California was the most resistant, while V7 was the least resistant to the hypochlorite solution.
将单核细胞增生李斯特菌菌株Scott - A在不同温度和pH值下用1 ppm有效氯进行处理。不同的单核细胞增生李斯特菌菌株（加利福尼亚株、Scott - A株和V7株）也在pH值为7且温度为25°C的条件下暴露于1 ppm有效氯中。单核细胞增生李斯特菌的初始菌量为每毫升次氯酸钠溶液1×10至3.2×10 CFU。通过对暴露于次氯酸钠溶液30秒至1小时的间隔时间采集的样本进行表面涂布（在胰蛋白胨琼脂上）来测定单核细胞增生李斯特菌的存活率。单核细胞增生李斯特菌菌株Scott - A在25°C下存活的数量比在35°C下更多。当细胞在5°C下暴露于次氯酸钠溶液时观察到存活数量最少。在pH值5至9的范围内，pH值越高，单核细胞增生李斯特菌菌株Scott - A的存活数量就越多。在所研究的菌株中，加利福尼亚株对次氯酸钠溶液的抗性最强，而V7株的抗性最弱。
