Characterization of probiotic Lactobacillus spp. isolates from commercial fermented milks
type: CreativeWork
description: The aim of this project was to study the identity of probiotic lactobacilli in fermented milk products from the United Kingdom/European markets during their survival during shelf-life. This in vitro study was also aimed at undertaking studies on some of the physiological probiotic criteria, such as resistance to stomach/intestine conditions and also possible functional properties of the isolates, such as antimicrobial activities, antibiotic resistance/susceptibility and antibiotic resistance genes, biofilm formation and production of conjugated linoleic acid (CLA). Primarily, a comparative study was carried out on selectivity of MRS-Clindamycin, MRS-Sorbitol and MRS-IM Maltose, to select the right medium for enumeration of probiotic Lactobacillus. Based on selectivity of medium for recovery of the targeted lactobacilli and also simplicity of preparation, MRS-Clindamycin was chosen as the best medium for enumeration of probiotic Lactobacillus in fermented milks. The results of enumeration of lactobacilli showed that 22 out of a total 36 tested products contained more than 106 colony forming units/g at the end of their shelf-life, which comply with the recommended minimum therapeutic level for probiotics. Rep-PCR using primer GTG-5 was applied for initial discrimination of isolated strains, and isolates, which presented different band profile, were placed in different groups. The isolated Lactobacillus spp. were identified mainly as Lactobacillus acidophilus, Lactobacillus casei and Lactobacillus paracasei by analysis of partial sequences of the 16S ribosomal RNA and rpoA genes. In order to characterize the isolates for probiotic properties, this study was focused on six Lactobacillus isolates along with two commercial Lactobacillus cultures from Chr. Hansen (Lactobacillus acidophilus La5 and Lactobacillus casei C431) and three Lactobacillus type strains (Lactobacillus casei subsp. casei, Lactobacillus paracasei subsp. paracasei and Lactobacillus acidophilus) which we…
abstract: The aim of this project was to study the identity of probiotic lactobacilli in fermented milk products from the United Kingdom/European markets during their survival during shelf-life. This in vitro study was also aimed at undertaking studies on some of the physiological probiotic criteria, such as resistance to stomach/intestine conditions and also possible functional properties of the isolates, such as antimicrobial activities, antibiotic resistance/susceptibility and antibiotic resistance genes, biofilm formation and production of conjugated linoleic acid (CLA). Primarily, a comparative study was carried out on selectivity of MRS-Clindamycin, MRS-Sorbitol and MRS-IM Maltose, to select the right medium for enumeration of probiotic Lactobacillus. Based on selectivity of medium for recovery of the targeted lactobacilli and also simplicity of preparation, MRS-Clindamycin was chosen as the best medium for enumeration of probiotic Lactobacillus in fermented milks. The results of enumeration of lactobacilli showed that 22 out of a total 36 tested products contained more than 106 colony forming units/g at the end of their shelf-life, which comply with the recommended minimum therapeutic level for probiotics. Rep-PCR using primer GTG-5 was applied for initial discrimination of isolated strains, and isolates, which presented different band profile, were placed in different groups. The isolated Lactobacillus spp. were identified mainly as Lactobacillus acidophilus, Lactobacillus casei and Lactobacillus paracasei by analysis of partial sequences of the 16S ribosomal RNA and rpoA genes. In order to characterize the isolates for probiotic properties, this study was focused on six Lactobacillus isolates along with two commercial Lactobacillus cultures from Chr. Hansen (Lactobacillus acidophilus La5 and Lactobacillus casei C431) and three Lactobacillus type strains (Lactobacillus casei subsp. casei, Lactobacillus paracasei subsp. paracasei and Lactobacillus acidophilus) which we…
author: Farahmand, Nasim
keywords: 640 Home & family management
date published: 2015-07
date modified: 2026-07-24T02:54:23Z
provider: London Metropolitan University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: London Metropolitan University