The investigation of the diversity of lactobacilli spp. and assessment their some probiotic properties in traditional dairy products in East Azerbaijan province in Iran

Nowadays, there is increasing interest in the production of functional foods, particularly probiotic foods. Lactic acid bacteria (LAB) particularly strains of Lactobacillus are important bacteria in food microbiology and human nutrition due to their ability to fermented food production and have received considerable attention as probiotics. The traditional fermented dairy foods as a rich source of wild LAB can be introduced new Lactobacillus strain with probiotic properties into food products. So, the present study was aimed to isolate and identify Lactobacilli spp. in traditional dairy products and assessing their some probiotic properties. For this study, fifty samples including homemade yogurt and cheese were purchased from several rural areas and the intragenic transcribed spacer-PCR (16-23s rDNA) was used for identification of Lactobacilli. Some probiotic properties were assayed including resistant to acid and bile, antimicrobial activity and antibiotic susceptibility.
The isolates were characterized as L.plantarum, L.casei, L.paracasei and L.rhamnosus. Out of the fifty six isolates identified phenotypically as lactobacillus, twenty four strains were tolerant to pH 2.5 and 0.3% bile salt after 3 h of incubation and only 6 strains showed antimicrobial activity and antibiotic susceptibility. In conclusion six strains showed potentially probiotic properties including resistant to acid and bile, antimicrobial activity and antibiotic susceptibility, so we can consider these strains as a native probiotic but extra examinations was required for introduction into food products.