Isolation of probiotic Lactobacilli from local dairy products in Tehran province

Background and Aim : Probiotics are live bacteria with valuable properties on genital and gastrointestinal health. The growth in the consumption of industrial dairy products instead of the traditional ones may enhance the possibility of missing the probiotic bacteria. The aim of this investigation is to isolate lactobacilli from local cheeses and yogurts produced in rural areas of Tehran province and also to assessment their antibacterial profile against common pathogenic bacteria.Methods : In current study, ۲۵ samples of local yogurts and cheeses from three separated rural areas were collected. Probiotic lactobacilli were isolated using MRS medium, selective screening methods, catalase test. Additionally resistance to bile and acidity and some relevant biochemical tests were carried out. Bactericidal effects of the isolated probiotics against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhimurium were assessed by using disk diffusion and well diffusion agar methods.Results : Out of the ۲۵ cheese and yogurt samples, ۱۲ isolates of acid-stable lactobacilli were selected at the first stage. At the next stages, ۵ isolates of acid-stable and bile-stable lactobacilli were isolated including: L. rhamnosus (in two places) L. casei, L. plantarum, and L. acidophilus. While the growth of the pathogenic bacteria was suppressed by all ۵ lactobacilli, L. casei and L. plantarum showed the strongest bactericidal effects.Conclusion : Local products may have probiotic bacteria with beneficial properties. These bacteria can be used for mass production of industrial dairy products.

کلیدواژه ها:

Probiotic Bacteria ، Antimicrobial ، Local dairy products.