期刊
FOOD RESEARCH INTERNATIONAL
卷 37, 期 9, 页码 839-850出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.foodres.2004.04.006
关键词
probiotic; Lactobacillus; Bifidobacterium; fermented milk
A selection of commercial fermented milks was evaluated for the presence and viability of probiotic lactobacilli and bifidobacteria. Counts of Lactobacillus spp. always remained higher than 10(5) CFU ml(-1), whereas the population of Bifidobacterium spp. decreased below this level in two products. All the probiotics announced on the label were present in commercial products, yet in two fermented milks one additional group of microorganisms was also found. The yogurt microorganism Streptococcus thermophilus was present in all cases, whereas Lactobacillus delbrueckii ssp. bulgaricus was only detected in two products. Bifidobacterium was the most frequently isolated group, all commercial strains being identified as Bifidobacterium animalisl Bifidobacterium lactis by analysis of partial sequences of the 16 rRNA gene. The same technique allowed the identification of members of Lactobacillus casei (species Lactobacillus caseil Lactobacillus paracasei/Lactobacillus zeae) and Lactobacillus acidophilus (species L. acidaphilus sensu stricto and Lactobacillus johnsonii). The analysis of macrorrestriction profiles by pulsed-field gel electrophoresis evidenced the reduced genetic variability existing among commercial Lactobacillus and Bifidobacterium strains. The combined use of macrorrestriction analysis and carbohydrate fermentation profiles enhanced the discriminatory power of the first technique for strains differentiation. None commercial Bifidobacterium strain presented the harmful P-glucuronidase activity whereas all of them displayed beta-galactosidase, beta-glucosidase and alpha-galactosidase activity. (C) 2004 Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据