15E-5 |
Growth inhibition on some food poisoning microorganisms by lactic acid bacteria isolated from feces of newborn baby |
D. H. SHIN1, J. Y. Lee, and Y. S. Kim. (1) Dept. Food Science & Technology, Chonbuk National University, 664-14, Dukjin-Dong, Dukjin-Gu, Jeonju, 561-756, South Korea
It is well known that lactic acid bacteria (LAB) can inhibit the growth of bacterial pathogens by lactic acid, bacteriocin, and peroxidase produced by LAB. Due to prophylactic and therapeutic properties of live LAB, many products fermented by LAB are in market now. The feces of newborn baby could be good source of LAB, which are easily adapted to human intestinal. The objective of this study was to isolate the LAB which have bile and acid resistant, and confirm the inhibition activities to some food poisoning bacteria (FPB). The feces from 61 healthy newborn baby were obtained and thoroughly mixed them with anaerobic solution. The mixtures were inoculated on LBS agar and incubated in anaerobic chamber at 35° C. The acid tolerance at pH 7.0, 3.0, and 2.3, and bile tolerance at 0.25-1.0% of bile salt to the isolates were conducted. Finally 17 isolates were screened and tested inhibition to L. monocytogenes, B. cereus, S. Typhimurium, S. Enteritidis, S. aureus, and E. coli O157:H7. After 24 hr incubation of each isolate in MRS broth, the filtrates of D2 and F35-2 strain inhibited growth of all FPB tested at 20% addition level in the broth. Co-incubation of FPB with D2 and F35-2 strain also reduced bacterial number in 3-8 log. Antimicrobial activities of the broth of D2 and F35-2 were reduced after neutralization but catalase treatment showed only to F20-3. The trypsin, pepsin, and heat treatment (121° C, 15 min) were not affecting the antimicrobial activity of test LAB. The isolates were identified as L. plantarum (D2) and L. fermentum (F20-3) by 16S rDNA sequencing method. The LAB isolated from feces of newborn baby can be utilized to control food poisoning bacteria in food processing and to develop new fermented products having probiotic effects because those have high bile and acid tolerance.
Session 15E, Nutraceuticals & Functional Foods I
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