In vitro Evaluation of Probiotic Activities of Lactic Acid Bacteria Strains Isolated From Novel Probiotic Dairy Products

Due to their increasing popularity among consumers the number of probiotic dairy products on the local market has increased tremendously during the last few years. Probiotic bacteria used in commercial products today are mainly members of the genera Lactobacillus and Bifidobacterium. Twenty lactic acid bacterial strains were isolated and identified by phenotypic method from samples of probiotic dairy products as fermented milk drinks, yoghurts and infant milk powder. These strains were grouped at species level as L. casi, L. acidophilus, L. plantarum and Bifidobacteria species. These strains were further tested for the presence of functional traits useful for probiotic applications, such as resistance to acidic condition at pH 2, bile salt hydrolytic activity and ability for adhesion to Caco-2 cells as well as ability to inhibit the adhesion of E. coli, Salmonella typhimurium and Shigella flexneri to caco-2 cells. Our obtained results showed that most of tested strains exhibited characteristics suggesting that they would survive in the gastrointestinal tract and also had the capability for adhesion to caco-2 cells. Greater variability was observed for the other traits analyzed. These data suggest that these probiotic strains had characteristic and differential functions traits. Therefore, results from our present study are expected to encourage people to consume more probiotic dairy products, as it was revealed that these products contain some probiotic lactic acid bacteria which play a major role for the beneficial health effects of consumers.