阪崎克罗诺杆菌
益生菌
食品科学
抗菌剂
开菲尔
微生物学
发酵
乳酸
细菌
微生物
化学
生物
婴儿配方奶粉
遗传学
作者
Dong‐Hyeon Kim,Dana Jeong,Kwang‐Young Song,Inpil Kang,Hyun‐Sook Kim,Kun‐Ho Seo
出处
期刊:Journal of Dairy Research
[Cambridge University Press]
日期:2018-02-01
卷期号:85 (1): 98-103
被引量:23
标识
DOI:10.1017/s0022029917000802
摘要
Cronobacter sakazakii is a life-threatening foodborne pathogen found in powdered infant formula and dairy products. Kefir is a dairy probiotic product and its antimicrobial activity against C. sakazakii was reported in our previous study. To identify key microorganisms that mediate growth suppression, we tested the antimicrobial activity of culture supernatants derived from lactic acid bacteria found in kefir. Lactobacillus kefiri DH5, L. kefiranofaciens DH101, and B ifidobacterium longum 7 20 (a commercial probiotic strain that served as a positive control) all significantly inhibited the growth of C. sakazakii ATCC 29544, delaying the initiation of exponential growth from 3 to 9 h in the nutrient broth. Among them, L. kefiri DH5 exerted the strongest antimicrobial effects against C. sakazakii , showing bactericidal effect at the addition of 300 µl of supernatant in 1 ml of nutrient broth. Interestingly, the supernatant of L. kefiri DH5 has higher pH and lower titrable acidity than that of L. kefiranofaciens DH101, suggesting metabolites produced by heterofermentation of L. kefiri acted more effectively to antagonise the growth of C. sakazakii . In addition, the supernatant of L. kefiri DH5 induced the leakage of cytoplasmic materials including nucleic acid and proteins, suggesting L. kefiri DH5 disrupted the cellular membrane integrity of C. sakazakii . Considering that pH neutralisation reduced the L. kefiri -dependent growth suppression, it is inferred that this activity is mainly due to organic acids produced during the fermentation process.
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