Isolation and characterization of probiotics from dairies

BACKGROUND AND OBJECTIVES: Probiotics are live microorganisms, which show beneficial health effects on hosts once consumed in sufficient amounts. LAB group can be isolated and characterized from traditional dairy sources. This study aimed at isolating, identifying, and in vitro characterizing (low pH/high bile salt tolerance, antibacterial activity, and antibiotic susceptibility) LAB strains from traditional Iranian dairy products. MATERIALS AND METHODS: Isolated strains were identified by Gram staining, catalase assay, and 3 molecular identification methods; namely, (GTG) 5-PCR fingerprinting, ARDRA, and 16S rDNA gene sequencing. RESULTS: A total of 19 LAB strains belonging to 4 genera (Lactococcus, Leuconostoc, Lactobacillus and Enterococcus) were identified. CONCLUSION: The experiments revealed that L. plantarum 15HN, L. lactis subsp. cremoris 44L and E. mundtii 50H strains, which were isolated from shiraz, cheese and shiraz, respectively, displayed a desirable tolerance to low pH and high bile salts, favorable anti-pathogen activity, and acceptable antibiotic susceptibility; hence, they could be considered as novel probiotic candidates and applied in the food industry.