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Discrimination of dairy industry isolates of the Lactobacillus casei group

Desai, A. R, Shah, Nagendra P and Powell, I. B (2006) Discrimination of dairy industry isolates of the Lactobacillus casei group. Journal of Dairy Science, 89. pp. 3345-3351. ISSN 1525-3198

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Lactobacilli are a major part of the microflora of the gut and of many fermented dairy products, and are found in a variety of environments. Lactobacillus casei, Lactobacillus paracasei, Lactobacillus rhamnosus, and Lactobacillus zeae form a closely related taxonomic group within the facultatively heterofermentative lactobacilli. The classification and nomenclature of these bacteria are controversial. In this study, relationships between these species were investigated using type strains and dairy industry isolates examined with DNA-based techniques and conventional carbohydrate use tests. Carbohydrate use patterns gave poor discrimination of some species, but DNA PCR using specific primers targeted to sequences of the 16S rRNA gene discriminated 4 types consistent with the currently recognized species. Pulsed-field agarose gel electrophoresis of chromosomal NotI restriction fragments identified 18 different band patterns from 21 independent Lactobacillus isolates and confirmed the identity of L. casei strains from 2 culture collections (CSCC 5203 and ASCC 290), both representing the type strain of L. casei. Some isolates were reclassified as L. rhamnosus, suggesting that the prevalence of L. rhamnosus as a natural component of the microflora of dairy foods and dairy environments has previously been underestimated. These methods can provide a practical basis for discrimination of the species and identification of individual industrial strains.

Item Type: Article
Uncontrolled Keywords: Lactobacillus casei, Lactobacillus paracasei, Lactobacillus rhamnosus, Lactobacillus zeae
Subjects: Historical > RFCD Classification > 320000 Medical and Health Sciences
Historical > Faculty/School/Research Centre/Department > School of Biomedical and Health Sciences
Depositing User: Ms Phung T Tran
Date Deposited: 11 Nov 2008 05:04
Last Modified: 11 Jul 2011 01:54
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Citations in Scopus: 44 - View on Scopus

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