Probiotics are live microorganisms which when supplemented in diet, provide numerous health benefits to consumer.Nowadays, excessive use of antibiotics, dietary modulations, immunosuppressive therapy and irradiation may alter the composition of gut flora. Therefore, introduction of beneficial microbial species to GI tract is recently considered to be potent method to re-establish the microbial equilibrium and prevent disease. Lactic acid bacteria are major contributors of probiotic preparations, among them, Lactobacillus, Bifidobacterium, Enterococcus, Bacillus and Streptococcus are most common. These probiotic strains have been shown to be effective in gastrointestinal diseases ranging from infantile diarrhoea, necrotizing enterocolitis, antibiotic-associated diarrhoea, relapsing Clostridium difficle colitis, Helicobacter pylori infections and inflammatory bowel disease. Strains to be considered as probiotics must be resistant to bile, hydrochloric acid and pancreatic juice in order to survive both acidic conditions of the stomach and alkaline conditions of the duodenum, have reduced intestinal permeability, adhesion ability, non-pathogenic and preferably from human origin. The present work was carried out to study the efficacy, safety and probiotic properties of anaerobic Lactobacillus strains isolated from cattle milk. A total of eight milk samples were collected and twelve isolates were obtained by culturing anaerobically. All in vitro screening assays were employed to evaluate isolated strains. Out of twelve, only four strains displayed good survivability at gastric pH 2.0, 0.3% bile and simulated oro-gastro-intestinal fluid. Also, these cultures demonstrated significantly high cell hydrophobicity and auto-aggregation ability. The other functional attributes were efficient bile salt hydrolase, cholesterol reducing ability in spent broth and inhibition of some gastrointestinal pathogens in vitro.

Keywords: Probiotics, Lactobacillus, Bifidobacterium, Gastrointestinal disease, Cattle milk.