Probiotic properties of bifidobacteria and lactobacilli isolated from local dairy products

Fourteen strains of lactobacilli and bifidobacteria were isolated from raw milk and fermented dairy products produced by local traditional industries. These strains were evaluated for potential use as probiotics based on their adhesion to intestinal epithelial cells, resistance towards acidic and bile conditions, and antimicrobial activities. All strains exhibited varying levels of adhesion properties on mucin that were strain-dependent. Although most strains tolerated acidic conditions of pH 2, 3, and 4, the viability of the Lactobacillus and Bifidobacterium strains was significantly (P < 0.05) reduced at pH 2. Most strains also tolerated bile conditions similar to that of the gastrointestinal tract. A higher inhibition was observed in the presence of deconjugated bile, such as cholic acid, compared to deconjugated bile, such as taurocholic acid. In addition, most strains also showed antimicrobial activity towards intestinal pathogens, such as Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Salmonella typhimurium, Bacillus subtilis, and Pseudomonas aeruginosa. The findings from this study show that strains of lactobacilli and bifidobacteria isolated from local dairy products may be promising probiotics for use as dietary adjuncts or the development of new functional foods.