The investigation of probiotic potential of lactic acid bacteria isolated from cow milk

Abstract

Probiotic strains can be isolated from many sources, for human applications one of the main criteria is being mammal origin. Cow milk is an important nutrient source for human. Lot of studies showed that this fluid has beneficial effects on the health of human. One reason of being beneficial is explaining by the microflora of cow milk including beneficial lactic acid bacteria. In this research work, 12 isolate were identified as lactic acid bacteria by biochemical characterization and further studied for probiotic activity. Among them 9 lactic acid bacteria was posseses probiotic activity. Six Lactobacilli stains were identified as Lactobacillus gasseri(1),Lactobacillus rhamnosus(1),Lactobacillus fermentum(2),Lactobacillus viridescens(3),Lactobacillus farciminis(1), Lactobacillus buchner(4). All of the bacilli isolates were selected to observe potential probiotic activity. These isolates showed resistance to stomach pH (pH 3.0), tolerance against 0.3% bile salt concentration and antimicrobial activity against Escherichia coli, Salmonella enteritids, Staphylococcus aureus, Listeria monocytogenes. The isolates were used to investigate the tolerances of the isolates to other stress conditions, such as, growth at different NaCl solution, growth at different temperatures and in the presence of 0.5% CaCO3. All of the isolate showed good tolerances in stress conditions. After investigation the probiotic properties of these isolates, they were identified by biochemical characterization techniques. It is observed that, cow milk is a source of potential probiotic strains.