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

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Chapter IV: Results
4.3 Survival after the successive passages through artificial saliva, gastric and intestinal
juice
Ninty-four isolates from pickle mango, garlic–chilli, Bhaati jaanr, Mahula liquor and
children’s faeces were screened for their survival under simulated gastrointestinal conditions.
Strains of Lactobacillus casei (LAM-1 and LAM-2), Lactobacillus delbrueckii (LKH-2 and
LKH-3), Lactobacillus helveticus (LKH-5), and Lactobacillus fermentum (Lamec-29), with
good gastrointestinal survival were then chosen for further studies of probiotic properties
(Fig. 4.1). All other strains, which did not survive under gastrointestinal conditions were not
investigated further. The viability of the Lactobacillus casei (LAM-1 and LA-1M) strains
upon successive passages through artificial saliva and gastric duodenum juices is shown in
Figure 4.1 A. Strain LAM-1 showed notable survival (75%) in simulated gastric and
intestinal transit, whereas 62% LAM-2 cells survived these conditions.
The slight decline in the live counts of Lactobacillus casei strain seemed to be due to
the effect of gastric juice (determined after 1 h incubation with simulated acid gastric juice
and before addition of artificial duodenum juice), because in the following stages of
incubation, cell counts did not changes more than approx. 1 log units. Tolerance of L. casei
LAM-1 towards duodenum juice was higher than that of L. casei LAM-2 which was more
sensitive to artificial duodenum juice. Strains belonging to the Lactobacillus fermentum
group showed a low variability in their survival. Some strains presented the best survival
rates in this study, even higher than those observed for the L. casei strains, for e.g., Lamec-29
with 82% survival rate (Fig. 4.1 C). Other strains (results not shown) failed to survive under
simulated gastric and intestinal condition, these strains were therefore not chosen for further
studies.