Fenlon D R, Wilson J
Bacteriology Department, North of Scotland College of Agriculture, Aberdeen, UK.
J Appl Bacteriol. 1989 Mar;66(3):191-6. doi: 10.1111/j.1365-2672.1989.tb02469.x.
Over 180 farm bulk milk tanks were tested for the presence of Listeria monocytogenes on three separate occasions which included periods when cows were grazing and confined inside on a silage diet. The incidence of L. monocytogenes contamination was low, ranging from 3.8% in the summer samples to 1.0% in October. The level of contamination was estimated to be lower than one L. monocytogenes bacterium per ml in positive samples, as most required cold enrichment of 10-20 ml volumes before recovery. The distribution was sporadic; only one farm gave positive isolations on all three sampling occasions, one other on two, and all others were from different farms. No correlation between the presence of L. monocytogenes and hygiene standards or the feeding of silage was found.
在三个不同时期对180多个农场的散装奶罐进行了检测，以确定是否存在单核细胞增生李斯特菌，这三个时期包括奶牛放牧期和圈养食用青贮饲料期。单核细胞增生李斯特菌的污染发生率较低，夏季样本中的污染率为3.8%，10月份为1.0%。据估计，阳性样本中的污染水平低于每毫升一个单核细胞增生李斯特菌，因为大多数样本在复苏前需要对10 - 20毫升的样本进行冷增菌。分布是零星的；只有一个农场在所有三次采样中都得到了阳性分离物，另一个农场在两次采样中得到阳性，其他所有阳性样本均来自不同农场。未发现单核细胞增生李斯特菌的存在与卫生标准或青贮饲料喂养之间存在相关性。
