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

Chapter II Review of Literature
mannose, maltose, lactose, dextrin. Does not ferment mannitol, sucrose, salicin, glycerol,
inositol, rhamnose, arabinose, xylose, raffinose, inulin, sorbitol, amygdalin, cellobiose,
melibiose, melezitose.
2.2.4 Taxonomic diversity of Lactobacillus
The human gastrointestinal tract contains hundreds of different bacterial species
(Tannock, 1995). Members of the genus Lactobacillus are commonly present and have
received considerable attention with respect to their putative health conferring properties as
probiotics (Goldin and Gorbach, 1992). Lactobacillus has worldwide industrial use as starters
in the manufacturing of fermented milk products. Moreover, some of Lactobacillus strains
have probiotic characteristics and are therefore included in fresh fermented products or used
in capsular health products, such as freeze-dried powder. The use of some Lactobacillus
strains as probiotics is based on studies shows that these species belong to the normal
intestinal flora and the strains have beneficial effects on human and animal health (Salminen
et al., 1996).
Major bacterial species isolated from human gastrointestinal tract fall generally into
three distinct categories. These include 1) organisms almost always present in large number,
and constituting the indigenous and resident flora, e.g. Bacteroides, Bifidobacterium; 2)
organisms normally present in small or moderate numbers, and part of the resident flora, e.g.
Enterobacteriaceae, Streptococcus and Lactobacillus; and 3) organisms present in small
numbers, probably contaminants from other regions of the body e.g. Staphylococcus,
Haemophilus, etc., or from the environment, e.g. Bacillus, Corynebacterium, which constitute
transient flora.
More specifically, organisms of the human gastrointestinal tract include diverse
bacterial genera or families, and are divided into the following three groups: 1) Lactic acid
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