|
Untitled 1
|
 |
ANNUAL CONFERENCE :: Abstract Library
Abstract Library
2003 Conference Abstract
| Type of Submission |
 |
Submission Type: |
Poster Presentation |
|
Subject Category: |
Applied Microbiology |
|
| Session Information |
|
Presentation Date: |
May 26, 2003 |
|
Abstract ID: |
A16 |
|
Session: |
Poster 1 |
|
Time: |
14:00 |
|
| Presenting Author |
|
| Other Authors |
|
M LACROIX, INRS-Institut Armand-Frappier
D ARCHAMBAULT, Université du Québec à Montréal
L LAMONTAGNE, Université du Québec à Montréal
D ROY, Centre de recherche et de développement sur les aliments
|
|
| Title |
|
Inhibition of pathogens by lactic acid bacteria strains in fermented milk |
|
| Abstract Text |
|
The inhibition potential of selected lactic acid bacteria (LAB) (Lactobacillus rhamnosus RW-9595M, L. rhamnosus ATCC 9595, Lactococcus lactis subsp. lactis ATCC 11454 and the commercial starter culture CL 1285) on the growth of various pathogens and indicators strains was studied. Growth inhibition was first demonstrated by an agar spot test and a well-diffusion assay, showing that inhibitory agents were secreted in the liquid broth. In separate experiments, proteases were added to suggest that the inhibition could be caused by a proteinaceous substance. Thereafter, the selected LAB strains were added (at a ratio of 104:1) in skim milk to compete with the pathogens (Escherichia coli, Staphylococcus aureus, Salmonella typhymurium, Listeria innocua). Without pH control, inhibition of the different pathogens occurred in 24 to 48 hours when mixed with the different LAB while the lactobacilli grew to 108-109 CFU/ml. When the pH was continuously stabilized to 6.5 during the fermentation process, the growth rate of pathogens co-inoculated with lactobacilli was reduced as compared to the control (pathogen alone). These overall results suggested that the inhibition was not due to pH alone, because an increase in the generation time of the pathogens was observed during the pH controlled fermentations. Moreover, the tested LAB were able to modulate the macrophagic activity. In conclusion, all LAB used in this study exerted an antimicrobial activity and can thus be considered as a potential biotherapeutic remediation of patients infected with intestinal pathogens. |
|
|
|
|
