To understand the role of lactobacillus as a member of normal enteric flora, following experiments were carried-out. Lactobacillus was isolated from a. fermented milk product purchased at the market. The effect of oxygen on the growth of lactobacillus was measured by spectrophotometry. The mutual influences on the multiplication among the lactobacillus isolated from the milk ´product and E.coli and enterococcus which were isolated from feces of normal_ adults were studied in vitro by colony counting method. .
The results obtained were summarized as follows:
1. Lactobacillus grew better at 5% CO, in air than in the air or in the anaerobic condition. ;
2. In the mixed culture of E.coli and lactobacillus, the growth of E.coli was significantly inhibited in comparison to that of´E.coli in pure culture. But the growth of lactobacillus was not affected. -.
3. In the mixed culture of enterococcus and lactobacillus, the growth of enterococcus was not affected while the growth of lactobacillus was significantly inhibited.
4. Final pH of the culture medium was the lowest in the pure culture of lactobacillus (pH3.8), and increased in the order of the mixed culture of enterococcus and lactobacillus (pH4.6), the pure culture of enterococcus (pH4.7), the mixed, culture. of E.coli and lactobacillus (pH4.8) and the pure culture of E.coli (pH5.3).
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