In:
Journal of Food Safety, Wiley, Vol. 35, No. 1 ( 2015-02), p. 108-118
Abstract:
This study aimed to identify and evaluate the probiotic properties of five E nterococcus strains isolated from the silage using in vitro screening assays. Their metabolites, antibiotic susceptibility, antimicrobial activity, as well as their survival in the gastrointestinal tract ( GIT ) and adhesive ability to human intestinal cells were investigated. Among eight selected antibiotics, all the isolates showed sensitive traits to six particular antibiotics including tetracycline and vancomycin. L 2– L 5 showed inhibition zones against E scherichia coli and S almonella except that L 6 only inhibited the growth of E . coli . The GIT proved that all the strains were able to survive in low pH and bile salt conditions and they all can adhere to LS ‐174 T intestinal cells. L 2 and L 5 were then chosen to examine their competition activity toward E . coli and inflammatory response. The results showed that both strains exhibited strong competition activities toward E . coli. The displacement ratios were 98.4 and 97.7%, respectively. Compared with E . coli , L 2 showed lower stimulation of interleukin ( IL )‐8 and IL ‐1 β , while L 5 induced higher levels of cytokines to provoke an inflammatory response. Finally, the in vivo effect of L 2 was investigated. The data showed that L 2 was harmless. The results obtained suggest that L 2 is potentially probiotic. Practical Application E nterococci are lactic acid bacteria that occur frequently in large numbers in various foods including vegetable, meat and dairy products. However, some of these bacteria are also recognized as nosocomial pathogens. Several properties may be evaluated to prove the potential of the bacteria before using them as probiotics. Results of this study indicated that five E nterococcus strains isolated from the mixed grass and corn stalk silage exhibited different capacties of antibiotic susceptibility, antimicrobial activity, tolerance to gastrointestinal conditions, adhesion to intestinal cells, and competitive exclusion of E . coli adhesion to epithelial cells and stimulation of immunity. Among these strains, L 2 shows above‐average results in all probiotic criteria observed in vitro . Additionally, L 2 was evaluated to be safe in mice feeding. The findings of our study suggest that L 2 isolated from the silage may be potentially used as probiotic in humans.
Type of Medium:
Online Resource
ISSN:
0149-6085
,
1745-4565
DOI:
10.1111/jfs.2015.35.issue-1
Language:
English
Publisher:
Wiley
Publication Date:
2015
detail.hit.zdb_id:
2179788-2
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