Lee Shin-Ho, Frank Joseph F
Department of Food Science and Technology, University of Georgia, Athens Georgia 30602.
J Food Prot. 1991 Jan;54(1):4-6. doi: 10.4315/0362-028X-54.1.4.
Inactivation by hypochlorite of Listeria monocytogenes cells adherent to stainless steel was determined. Adherent cell populations were prepared by incubating stainless steel slides with a 24 h culture of L. monocytogenes for 4 h at 21°C. Adherent microcolonies were prepared by growing L. monocytogenes on stainless steel slides submerged in a 1:15 dilution of tryptic soy broth at 21°C. The slides were then rinsed and transferred to fresh sterile broth every 2 d with a total incubation time of 8 d. Although the 4 h and 8 d adherent populations were at similar levels, 8 d adherent cells were over 100 times more resistant than the 4 h adherent cell population when exposed to 200 ppm hypochlorite for 30 s. When stainless steel slides containing adherent cells were heated at 72°C both adherent cell populations were inactivated after 1 min. Detectable numbers of L. monocytogenes remained on stainless steel slides after treatment at 65°C for 3 min when adherent 8 d cells were tested but not when adherent 4 h cells were used.
测定了次氯酸盐对附着在不锈钢上的单核细胞增生李斯特菌细胞的灭活效果。通过将不锈钢载玻片与单核细胞增生李斯特菌的24小时培养物在21°C下孵育4小时来制备附着细胞群体。通过将单核细胞增生李斯特菌在浸没于1:15稀释胰蛋白胨大豆肉汤中的不锈钢载玻片上于21°C培养来制备附着微菌落。然后每隔2天将载玻片冲洗并转移到新鲜无菌肉汤中，总孵育时间为8天。尽管4小时和8天的附着细胞群体数量相似，但当暴露于200 ppm次氯酸盐30秒时，8天附着细胞的抗性比4小时附着细胞群体高100倍以上。当含有附着细胞的不锈钢载玻片在72°C加热时，两种附着细胞群体在1分钟后均被灭活。当测试8天附着细胞时，在65°C处理3分钟后，不锈钢载玻片上仍有可检测数量的单核细胞增生李斯特菌，但使用4小时附着细胞时则没有。
