McKinnon C H, Pettipher G L
J Dairy Res. 1983 May;50(2):163-70. doi: 10.1017/s0022029900022962.
Samples of winter bedding and summer pasture, rinses of teats and milking equipment, and milk samples from bulk tanks from 4 farms were analysed bacteriologically for total count (TC), thermoduric count, total spore count (TSC) and psychrotrophic spore count (PSC). In bedding and pasture samples the TSC comprised the main component of the thermoduric flora but was less than 0.1% of the TC. The PSC formed approximately 1% of the TSC in winter bedding and approximately 23% of the TSC in pasture. For pasture, the PSC:TSC ratio was highest for the upper layer of soil and lower for the grass and deeper layer of soil. The TSC formed 5% of the thermoduric flora in rinses of milking equipment and only a very low PSC was obtained. The TSC of farm bulk tank milks was higher in the winter than the summer but the PSC was similar in both seasons. This was due to an increase of approximately 9 times in the PSC:TSC ratio for milks in summer compared with winter. The PSC in raw and commercially pasteurized milks from a local creamery showed a similar seasonal trend.
对4个农场的冬季垫料和夏季牧场样本、乳头冲洗液和挤奶设备冲洗液以及奶罐中的牛奶样本进行了细菌学分析，以检测总菌数（TC）、耐热菌数、总芽孢数（TSC）和嗜冷芽孢数（PSC）。在垫料和牧场样本中，TSC是耐热菌群的主要组成部分，但不到TC的0.1%。PSC在冬季垫料中约占TSC的1%，在牧场中约占TSC的23%。对于牧场，土壤上层的PSC:TSC比值最高，草层和土壤深层的比值较低。TSC在挤奶设备冲洗液中占耐热菌群的5%，且仅获得非常低的PSC。农场奶罐牛奶的TSC冬季高于夏季，但两个季节的PSC相似。这是因为与冬季相比，夏季牛奶的PSC:TSC比值增加了约9倍。当地一家乳制品厂的生牛奶和商业巴氏杀菌牛奶中的PSC呈现出相似的季节性趋势。
