Document Detail

Survival of lactic acid bacteria from fermented milks in an in vitro digestion model exploiting sequential incubation in human gastric and duodenum juice.
MedLine Citation:
PMID:  22281320     Owner:  NLM     Status:  In-Data-Review    
In the present study, the survival of 9 lactic acid bacteria (5 Lactococcus strains, 3 Lactobacillus strains, and 1 strain of Enterococcus hirae), was investigated in vitro under conditions similar to human digestion using human gastric and duodenal juices. The tolerance of the bacteria was also tested with traditional methods using acidic conditions and bile salts. The strains were subjected to a model digestive system comprising sequential incubation in human gastric and duodenal juices, in a 2-step digestion assay at 37°C, simulating the human upper gastrointestinal tract with human gastric juices at pH 2.5 and human duodenal juices at pH 7. The bacterial strains were tested either as washed cells from culture media or in fermented milk. The initial in vitro testing in acid and bile salts showed that Lactobacillus strains and the E. hirae strain displayed a significantly higher acid tolerance than the lactococci. The lactobacilli and the Enterococcus numbers increased, whereas the lactococci decreased at least 1 log during the bile salt treatment. The Lactobacillus strains showed the highest survival rate in the model digestive system when washed bacterial cultures were used with a minor log reduction, whereas the lactococci numbers were reduced by at least log 4. However, when using fermented milks in the model digestion system it was demonstrated that the Enterococcus strain and 2 strains of Lactococcus lactis ssp. cremoris benefited significantly from the presence of the fermented milk as food matrix, with log numbers >log 7 and 5, respectively, after digestion of the fermented milk. The analyses reported comprise a comprehensive in vitro testing regimen suitable for evaluation of the survival of candidate probiotic bacteria in human digestion as an initial prescreen to clinical trials.
T Faye; A Tamburello; G E Vegarud; S Skeie
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of dairy science     Volume:  95     ISSN:  1525-3198     ISO Abbreviation:  J. Dairy Sci.     Publication Date:  2012 Feb 
Date Detail:
Created Date:  2012-01-27     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  2985126R     Medline TA:  J Dairy Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  558-66     Citation Subset:  IM    
Copyright Information:
Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Department of Chemistry, Biotechnology and Food Sciences, Norwegian University of Life Sciences, PO Box 5003, NO-1432 Ås, Norway.
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