Characterization and screening of the potential probiotic lactic acid bacteria strains isolated from traditional dairy products

Background and Aim : Probiotics are living microorganisms that provide beneficial properties to the host. Due to their health properties, they are widely used in the pharmaceutical and food industries. Traditional dairy products are the natural habitats of microbes, especially lactic acid bacteria (LABs). Lactic acid bacteria are the largest group of probiotics. These bacteria must tolerate to harsh gastrointestinal conditions until they reach the target point, and then they can offer their physiological activities and beneficial capabilities.Methods : The aim of this study was to screen and select potent probiotic LAB strains isolated from different traditional dairy products and to evaluate the feasibility of their use in the production of probiotic products. From ۱۲۰ samples collected from different dairy products, ۱۸۰ bacterial isolates were isolated in four different media. Probiotic characteristics of isolated bacteria were determined based on acid tolerance, bile tolerance, and tolerance to digestive enzymes pepsin and trypsin tests.Results : Of the ۱۸۰ isolates studied, ۲۳ microorganisms were resistant to bile, ۵ isolates were resistant to acid, pepsin, and trypsin. These five resistant isolates were identified by ۱۶S rRNA gene sequence analysis as Lactobacillus delbrueckii (n=۲), Lactobacillus acidophilus (n=۱), Lactobacillus gasseri (n=۱), and Lacticaseibacillus rhamnosus (n=۱). Conclusion : In the present study, the isolated lactic acid strains had good probiotic potential and high resistance at low pH and digestive enzymes. Further studies such as the safety assessment of these strains are needed to introduce these samples as probiotic strains.

Keywords:

Probiotics , Lactic acid bacteria , traditional dairy productsi , Lactobacillus.