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

I.Introduction
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Chapter I: Introduction
Lactic acid bacteria (LAB) including Lactobacillus spp. such as Lactobacillus
acidophilus, Lactobacillus plantarum, Lactobacillus johnsonii, Lactobacillus gasseri,
Lactobacillus casei, Lactobacillus delbrueckii, Lactobacillus plantarum, Lactobacillus
rhamnosus and Bifidobacterium spp. have been recognized to be important in the
maintenance of the human intestinal microbial ecosystem. Member of LAB are widely-used
probiotics in fermented foods and beverage industry and also contributes to the sensory
qualities of the food and also in the prevention of spoilage. These organisms are present in
large number in normal animal gastrointestinal flora (Sgouras et al., 2004). Improvement in
intestinal disorders and lactose intolerance, altered vitamin content of milk, antagonism
against various pathogenic organisms and antimutagenic and anti-carcinogenic activities are
some of the health benefits of LAB.
The beneficial properties associated with lactobacilli fermented food would improve
health was postulated in the beginning of the 20 th
century by Metchnikoff (1908). He related
the longevity of the Caucasians to the consumption of fermented milk products with
Lactobacillus bulgaricus. Since then, these organisms have created a new generation of
health foods in human nutrition. These health foods were termed as ‘probiotic’ by Fuller
(1989), which means a live microbial feed supplement that beneficially affects the host by
improving its intestinal microbial balance. The definition of probiotics has been modified and
improved several times; a consensus definition had been stated by Schrenzenmeir and de
Verse (2001). They defined probiotics as ‘a preparation or product containing viable, defined
micro-organisms in sufficient numbers that alter the microflora in a compartment of the host
and that exerts health effects in the host’.