Discipline: dairy & health; Keywords: probiotics, Lactobacillus, antibiotic sensitivity, antimicrobial activity, acid and bile resistance.
The purpose of the study by the authors cited below was to characterize Lactobacillus isolates from bovine and dairy origin for their probiotic attributes, with the aim of assessing their safety for human use. The probiotic properties evaluated were acid and bile resistance, bile salt hydrolase activity, antimicrobial activity, antibiotic sensitivity, gelatinase and lipase production, and hemolytic activity.
All four strains studied, including the ATCC control, showed moderate to better ability to survive in the acidic conditions at pH 5 and pH 3, but loss their viability significantly at pH 2. The isolates tolerated 0.3% bile salts, and they all secreted bile salt hydrolase enzymes. All strains showed resistance to the antibiotics kanamycin and vancomycin, but showed susceptibility to gentamicin, clindamycin, erythromycin, tetracycline, ampicillin and chloramphenicol. The isolates from bovine origin were moderately susceptible to tetracycline. In antimicrobial activity assay, the strains showed excellent antimicrobial activity against diarrheagenic E. coli and pathogenic Candida spp. Furthermore, the study isolates were lipase and gelatinase negative, but they have shown α- hemolysis which is the partial hydrolysis of red blood cells. The performance characteristics of all the four lactobacilli isolates were identified and compared. Though all the strains possess excellent probiotic potential, the rumen isolates have shown slightly increased tolerance to human gastrointestinal conditions.
In conclusion: The study showed that the isolates had a slightly improved tolerance to stressful conditions of typical inhibitory activity against pathogens and exposure to bile salts. The probiotic characteristics evaluated from the dairy and bovine sources proved that they can be further exploited in fermentation (e.g. yogurt) and the larger food industry. Valuable information has been gathered on bovine and dairy isolates which will be key in identifying potential probiotic strains of significance to the dairy industry, as well as the wider cosmetic and pharmaceutical industries.
E. M. Buys, S. Krishnamoorthy, R. Nyanzi & M. Mungwari, 2021. Probiotic and technological properties of lactic acid bacteria from bovine origin. Faculty of Natural and Agricultural Sciences, Department of Consumer and Food Sciences, University of Pretoria, Private bag X20, Hatfield 0028,Pretoria, South Africa