Characterization and screening of the potential probiotic lactic acid bacteria and Bifidobacterium strains isolated of different biotopes

The use of lactic acid bacteria (LAB) and bifidobacteria species as probiotics may help to reduce antibiotic use for therapeutic, prophylactic and growth promotion in animal husbandry. The choice of the starter cultures has a critical impact on the palatability, processability and nutritional attributes of fermented products. In our research, the aim of this study was to screen and select potent probiotic LAB and Bifidobacterium strains isolated from different niches and to evaluate their characteristic features. A total of fourteen LAB and fifty-four Bifidobacterium were isolated from four fresh cows and camel's milk, and twenty stool samples of healthy new born infants were identified and characterized by morphology and biochemical tests in order to select most suitable strains according to their technological characteristics including probiotic proprieties, antibiotics resistance and in vitro antagonism against food-poisoning bacteria. When the results of tolerance to both gastric and bile juices are taken together it appears that between fourteen LAB and forty-five, the strain B. longum BHI 07 has significantly the highest ability to survive during gastrointestinal transit (P < 0.05). Therefore, the mixed cultures of Bf. longum strains with LAB strains were more active against pathogenic bacteria than the pure one. These results show that bifidobacteria isolated from infants may be useful for improving probiotic formulae with respect to protection against pathogenic bacteria responsible of infection.