PHENOTYPIC CHARACTERIZATION AND IN VITRO SCREENING OF LACTIC ACID BACTERIA FROM GOAT MILK FOR PROBIOTIC USE

Abstract

A study was carried out to isolate and identify probiotic Lactic acid bacteria (LAB) from milk of West African Dwarf (WAD) goats. Fifty LAB strains were isolated from WAD goat milks and tested for in- vitro antibiotics susceptibility, tolerance to bile, resistance to low pH values and haemolytic activity. Sixteen isolates were found to possess probiotic characteristics and these isolates were identified as Lactobacillus plantarum (44%), L. acidophilus (38%) and L. fermentum (18%). These isolates were resistant to most of antibiotics tested, showed the survivability (8.00 ± 0.05 to 72.60 ± 0.1%) at high bile acid concentration and resistance to pH 1.5 (0.00 to 46.00 ± 0.2%), pH 2.0 (30.60 ± 0.15 to 63.00 ± 0.6%) and pH 2.5 (48.60 ± 0.03 to 85.20 ± 0.6 %). None of the LAB isolates produced hemolysin. Among the probiotic isolates, Lactobacillus acidophilus displayed strong bile acid and low pH tolerance, followed by Lactobacillus plantarum. From the results obtained, L. acidophilus and L. plantarum could be used as probiotic starter cultures for fermented dairy foods as well as feed additives in livestock production due to high tolerance to high bile and acidic medium.