Phillips J D, Griffiths M W
J Appl Bacteriol. 1986 Oct;61(4):275-85. doi: 10.1111/j.1365-2672.1986.tb04288.x.
The seasonal variation in the spoilage of pasteurized products, especially double cream, by spore-forming bacteria was due to a number of factors. By far the most important was the seasonal variation in the types of organisms isolated from raw milks. Psychrotrophic spore-formers predominated in the summer-autumn months and these strains were able to germinate rapidly and grow in refrigerated dairy products. There was evidence that the concentration of one or more factors which promoted germination of psychrotrophic strains of Bacillus spp. in milk was higher during the summer than in the winter. This again may contribute to seasonal differences in spoilage by spore-forming bacteria. Post-heat treatment contamination by spores of Bacillus spp. may also be more prevalent in the summer-autumn period and evidence was obtained that spores associated with post-pasteurization contamination could germinate and grow more rapidly than those introduced into the product from the raw material. Thus, the increased spoilage of pasteurized products by Bacillus spp. observed in the June to October period may be due to a combination of factors. The relative contribution that each makes is not easily resolved.
巴氏杀菌产品，尤其是双层奶油，被产芽孢细菌腐败的季节性变化是由多种因素造成的。迄今为止，最重要的因素是从原料乳中分离出的微生物类型的季节性变化。嗜冷产芽孢菌在夏秋季占主导地位，这些菌株能够在冷藏乳制品中迅速发芽并生长。有证据表明，促进芽孢杆菌属嗜冷菌株在牛奶中发芽的一种或多种因素的浓度在夏季高于冬季。这同样可能导致产芽孢细菌腐败的季节性差异。夏季至秋季期间，芽孢杆菌属孢子的热处理后污染也可能更为普遍，并且有证据表明，与巴氏杀菌后污染相关的孢子比从原料引入产品中的孢子发芽和生长得更快。因此，在6月至10月期间观察到的芽孢杆菌属导致巴氏杀菌产品腐败增加可能是多种因素共同作用的结果。每种因素的相对贡献不容易确定。
