In-vitro probiotic evaluation of Lactobacillus species

Abstract

Probiotics are health promoting viable microorganisms that exhibit beneficial effects on the health of humans and animals. Lactobacillus species were isolated from nono and kunun zaki local drinks and the pH, bile salt and temperature tolerance of all the isolates were tested. Most of the isolates were shown to be able to tolerate a pH range of 2.0 to 7.0 except L. fermentum and L. oris which were unable to tolerate the pH of 2.0. However, all the Lactobacillus species were unable to tolerate the pH of 1.0. The Lactobacillus species isolated were able to survive in a range of 0.5 to 2.0 % bile salt concentrations and at a temperature range of 25 to 40^○C. The Lactobacillus species exhibited remarkable tolerance to stress factors which confers on them useful probiotic characteristics. Thus, they can be used as potential probiotic strains, both by serving as antagonistic agents to prevent harmful bacteria from colonizing the gastrointestinal tracts and other body parts as well as bio-preservatives even in foods with extreme physicochemical conditions such as acidic foods. Local food and beverage manufacturers were advised to exploit commercially prepared cultures of these strains as useful natural additives in their products.