Isolation, Characterization and Antimicrobial Activity of Lactic Acid Bacteria from Local Milk and Milk Products

Abstract

In the present study fifteen Lactic Acid Bacteria (LAB) from milk and milk products were isolated, identified and tested for their antagonistic activity. All the samples were found to be acidic with a pH range of 6.0 to 6.8.The collected samples showed higher number of total bacterial load ranging from 3.24´10 5 to 1.04´10 8 cfu/ml. Out of fifteen isolates, nine isolates were found to belong to the genus Lactobacillus and identified as L. casei subsp. pseudoplantarum, L. homohiochii, L. salivarius, L. xylosus, L.fermentum, L.leichmannii , L.heterohiochii, L.casei, and L.plantarum,.The others were found to belong to the genus Streptococcus and identified as S. thermophilus , S. lactis, S. uberis, S.suis, S. faecalis, and S. equnius.The isolates showed antibacterial activity against four gram positive bacteria (Bacillus cereus, B. subtilis, B.megaterium, Staphylococcus aureus) and six gram negative bacteria (Escherichia coli, Shigella dysenteriae, Salmonella typhi, Salmonella paratyphi, Vibrio cholerae and Pseudomonas aeruginosa) by using the disc diffusion method. They also showed their antifungal activity against two fungi (Penicillium sp. and Aspergillus flavus) by modifying poisoned food technique. All of the fifteen isolates were active against one or more test pathogenic bacterial strains. Among them L. homohiochii (TM3/a) showed the highest zone of inhibition (30.3mm) against Salmonella typhi. Lactobacillus spp. showed more antifungal activity than Streptococcus spp. and Streptococcus uberis (TY4 /a) showed the highest antifungal activity (50%) against Penicillium sp.This preliminary work shows the potential application of LAB to improve safety of traditional fermented food and milk products.Bangladesh J Microbiol, Volume 29, Number 2, Dec 2012, pp 76-82

Lactobacillus xylosus isolated from butter showed potentiality to be used as probiotic and biopreservative

“…All these evidences obviously suggest Lactobacillus xylosus MB1 to be a prospective candidate for probiotic bacteria. Probiotic lactic acid bacteria (LAB) have protective effects on human health including boosting of the immune system, inhibition of the growth of pathogens, prevention of diarrhea from various causes, prevention of colorectal cancer, reduction of the risk of inflammatory bowel movements, improvement of digestion of proteins and fats, synthesis of vitamins and detoxification and protection from toxins (Chowdhury and Ferdouse, 2012). Based on the beneficiary effects and more secured aspects of probiotic therapy than pharmaceutical agents (Bengmark, 2002) current study isolate Lactobacillus xylosus MB1 can be used as probiotics because there are historical data supporting the safety of lactobacilli for human use (Adams and Marteau, 1995).…”

“…Lactic acid bacteria (LAB) are a major broad group of probiotic bacteria. LAB are gram positive, non-sporing, catalase negative, cocci-shaped, usually non-motile organisms that are devoid of cytochrome C and are nonaerobic, but are aerotolerant and acid tolerant which produce lactic acid as the major end product (Agrawal, 2005;Nami et al, 2019;Chowdhury et al, 2012). These microbes are ubiquitous in nature and are indigenous inhabitants of the human gastrointestinal tract, vagina and human skin, but are also found in soil, water, vegetables products, meats, fermented and cooked meat and dairy products (Andersson et al, 2001;Li et al, 2018).…”

“…Lactobacillus and Streptococcus spp. are most commonly used probiotics in commercial fermented and non-fermented milk product now a days (Chowdhury et al, 2012). Some strains even contribute to the preservation of fermented milk and foods by producing bacteriocins (Ten Brink et al, 1994).…”