Study the effect of probiotic bacteria isolated from foods on pathogens

Abstract

Eleven Bacillus strains were isolated from foods and evaluated their probiotic potential and safety. Then study the effect of selected strains against pathogens, and on the population of pathogens in Reconstituted Skim Milk (RSM). Seven strains from Bacillus sp. (3) and Bacillus subtilis (4) were selected which were grow in low pH 1.0 to 5.0 and tolerant bile salt 0.3 to 2%, highly resistant to simulated gastrointestinal tract conditions, and showed antimicrobial activity against Salmonella typhimurium ATCC20231 and Staphylococcus aureus ATCC25923. They had antibiotic susceptibility against 6 tested antibiotics. Also, it’s exhibited non-hemolytic on sheep blood. Two pathogens were completely inhibited after 60 and 72hrs of incubation with selected probiotic strains in RSM. The results indicate that Bacillus subtilis or Bacillus sp. could be used as probiotic cultures for animal feeds and human, fermented vegetables, milk, meat product as well as to achieve bio preservation of dairy products in food industries.