from indigenous fermented foods and human gut ... - Thapar University

4.1 Isolation of Lactobacilli
IV. RESULTS
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Chapter IV: Results
A general agreement among those in favour of the classical definition of probiotics
refers to the need of live microorganisms exerting health-promoting effects, thus the need of
survival to host conditions to reach the site of action. The general criteria for selection of
strains to be used as probiotics include: safety and origin of the bacteria, their tolerance to the
hostile conditions of the stomach and the small intestine, and their ability to adhere to gut
epithelial tissue. GRAS (generally recognised as safe) microorganisms include Lactobacillus
spp. and Bifidobacterium spp., with a long history of safe use as they are being consumed by
humans for centuries. Selection of the strain regarding host species and location specificity
plays an important role if colonisation is essential for achieving the desired effect of the
probiotic.
The bacterial isolates screened for potential probiotics in this study were isolated from
traditionally fermented food and beverage products (namely mango pickle, garlic-chilli
pickle, chilli pickle, teak pickle, Kharoli (fermented mashed mustard), Bhaati jaanr
(fermented rice), Mahula liquor and human faeces. In the present study, a total of two
hundred and ninety six selected samples especially from traditionally fermented food were
collected from different locations of India and subjected for isolation of predominant
probiotic cultures. Predominant colony types were selected and purified by continuous
streaking on MRS media. Two hundred thirty four strains of lactic acid bacteria (LAB) were
isolated on this non selective media (MRS) from traditionally fermented food. Further
selective media Rogosa Agar was used for selective enumeration of Lactobacillus spp. from
these LAB isolates. By selective enumeration, 96 out of 436 strains were found to be species