Jensen M P, Ardö Y, Vogensen F K
Department of Food Science, Faculty of Life Sciences, University of Copenhagen, Frederiksberg C, Denmark.
Lett Appl Microbiol. 2009 Sep;49(3):396-402. doi: 10.1111/j.1472-765X.2009.02673.x. Epub 2009 Jun 10.
To isolate cultivable thermophilic lactic acid bacteria from cheeses made with mesophilic starter and compare them with dairy-related Lactobacillus helveticus strains using molecular typing methods.
The number of thermophilic bacteria in seven commercial cheeses manufactured with mesophilic starters was estimated to be <10 CFU g(-1). Implementation of an enumeration step in the isolation method made it possible to isolate one thermophilic strain from each of five of seven cheeses. Comparing repetitive sequence PCR (rep-PCR) profiles of the isolates with dairy-related Lact. helveticus strains indicated that one isolate was a Lact. helveticus. Partial sequencing of 16S rRNA confirmed this, and the remaining four strains were identified as Lactobacillus delbrueckii, Lactobacillus fermentum and Enterococcus faecium. The rep-PCR profile of the isolated Lact. helveticus was identical to the rep-PCR profile of the Lact. helveticus adjunct culture used in the specific cheese, but their pulsed field gel electrophoresis profiles differed slightly.
It was possible to isolate cultivable thermophilic bacteria from ripened cheeses manufactured with mesophilic starter and thermophilic adjunct cultures by using an enumeration step.
Isolation of cultivable thermophilic bacteria from ripened cheeses made with mesophilic starters offers an original source for new dairy-relevant cultures.
从使用嗜温发酵剂制作的奶酪中分离可培养的嗜热乳酸菌，并使用分子分型方法将其与乳制品相关的瑞士乳杆菌菌株进行比较。
估计使用嗜温发酵剂生产的七种市售奶酪中嗜热细菌的数量<10 CFU g(-1)。在分离方法中实施计数步骤使得能够从七种奶酪中的五种奶酪中各分离出一株嗜热菌株。将分离株的重复序列PCR（rep-PCR）图谱与乳制品相关的瑞士乳杆菌菌株进行比较，结果表明有一株分离株为瑞士乳杆菌。16S rRNA的部分测序证实了这一点，其余四株菌株被鉴定为德氏乳杆菌、发酵乳杆菌和粪肠球菌。分离出的瑞士乳杆菌的rep-PCR图谱与特定奶酪中使用的瑞士乳杆菌辅助培养物的rep-PCR图谱相同，但其脉冲场凝胶电泳图谱略有不同。
通过使用计数步骤，可以从使用嗜温发酵剂和嗜热辅助培养物制作的成熟奶酪中分离出可培养的嗜热细菌。
从使用嗜温发酵剂制作的成熟奶酪中分离出可培养的嗜热细菌为新的乳制品相关培养物提供了一个原始来源。
