We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Selection of acid tolerant Bifidobacteria and evidence for a low-pH-inducible acid tolerance response in Bifidobacterium longum.
- Authors
Noritoshi Takahashi; Jin-Zhong Xiao; Kazuhiro Miyaji; Tomoko Yaeshiima; Akinori Hiramatsu; Keiji Iwatsuki; Sadayuki Kokubo; Akiyoshi Hosono
- Abstract
Acidity is an environmental condition commonly encountered by lactic acid bacteria and bifidobacteria in the gastrointestinal tract and fermented foods. In the present study, 22 strains of Bifidobacterium were screened for acid tolerance in artificial gastric juice (AGJ, pH 3·0) and fermented milk. AGJ tolerance was found to be strain-specific, with a pronounced variation among the strains. Several strains with a high survival rate in AGJ that belonged to Bifid. longum, Bifid. breve and Bifid. adolescentis were selected. Among them, only strain BL1 of Bifid longum was found to possess a high survival rate in fermented milk during refrigerated storage. Strain BL1 exhibited a survival rate of more than 25% in AGJ at pH 3·0 for 2 h and maintained a viable cfu level of more than 108 per gram of product in fermented milk (pH 4·6) under refrigerated conditions for 2 weeks. The acid tolerance of strain BL1 was found to depend on the final growth pH (<4·5). Rapid loss of acid tolerance was observed when the cells were shifted from acid to neutral conditions by addition of NaOH. Strain BL1 cells were able to maintain much higher intracellular pH under acid conditions, in comparison with those of AGJ sensitive mutant (BL1-S) or cells that lost acid tolerance following pH shifting from acid to neutral conditions. These results suggested that a cytoplasmic pH homeostasis system may function in the acid tolerance response in this strain.
- Subjects
BIFIDOBACTERIUM; FERMENTATION; LACTIC acid; GASTRIC juice; HOMEOSTASIS; DAIRY products; MANUFACTURING processes
- Publication
Journal of Dairy Research, 2004, Vol 71, Issue 3, p340
- ISSN
0022-0299
- Publication type
Article
- DOI
10.1017/s0022029904000251