醱酵乳에서 分離된 乳酸菌이 大腸菌의 發育에 미치는 影響에 對한 硏究 = Study on the Effects of Lactic acid Bacteria Isolated From a Fermented Milk on the Growth of Escheichib coli

다국어 초록 (Multilingual Abstract)

The purpose of this experiment was to study on the effects of lactic acid bacteria on the growth of Escherichia coli that was cultured with Lactobacillus casei, Lactobacillus bulgaricus, Lactobacillus acidophilus and Streptococcus thermophilus isolated from a fermented milk, respectively, in three different media.
The growth inhibition of E. coli by fermentation of L. casei and L. bulgaricus was observed within 8hrs in all media, and by that of L. acidophilus was observed within 8hrs in A-and B-medium but 16hrs in skimmilk, and by that of S. thermophilus was observed within 24hrs in A-medium and skimmilk but within 8hrs in B-medium.
The inhibitory efficacy of Lactobacillus to E. coli in all media were above 99% but that of S. thermophilus in B-medium and skimmilk was above 99%, and was 76% in A-medium.
The final pH of A-and B-medium that inhibited the growth of E. coli by L. casei was 5.3, and 5.4 by L.bulgaricus and L. acidophilus respectively, but was 4.9 in A-medium and 5.4 in B-medium by S. thermophilus.
The pH of skimmilk that inhibited the growth of E. coli by lactic acid bacteria ranged from 4.5 to 5.8, and when the bacilli were cultured for 48hrs, the final pH of A-and B-medium ranged from 4.1 to 4.2 but that of skimmilk ranged a little widely from 3.3 to 4.3.