Screening of probiotic characteristics of lactic acid bacteria isolated from some fermented nigerian food products

Abstract

Microorganisms that exert health benefits to the host when consumed in the right proportion are termed Probiotics. Certain lactic acid bacteria, especially Lactobacillus spp. have been considered to be probiotics with proven health benefits and have been used widely in human health management. In this study, in vitro and in vivo evaluation of probiotics characteristics of Lactic acid bacteria (LAB) isolated from traditional Nigerian fermented food products (Ogi and Kunu-zaki) was carried out. Ethical approval was obtained from Covenant Health Research Ethics Committee (CHREC). Ogi and Kunu-zaki were plated on de Mann Rogosa (MRS) agar, and Lactobacillus spp. were isolated and identified by morphology and biochemical characteristics. The probiotic characteristics such as acid and bile salt tolerance, antibiotic susceptibility and haemolytic activity were performed. A total of 15 lactic acid bacteria was isolated. Only 4 (26.7%) of the isolates have high tolerance at pH values 2, 4, and 6.5 for 6 h and hence were reported. The four acid-tolerant isolates showed higher survival rates to 0.1 and 0.3% bile salt for 3 h. All bile and acid tolerant isolates showed different sensitivity to various antibiotics used. Two out of the four probiotics were found to survive the gastrointestinal tract of male albino Wistar rats when they were given a daily dose of 1x109 cfu/mL for two weeks. The four probable Lactobacillus spp. were found to possess characteristics of probiotics and could have the ability to confer health benefits.