Isolation and Characterisation of Lactic Acid Bacteria from Raw and Fermented Milk

Abstract

The aim of this study was to isolate and phenotypically characterised lactic acid bacteria (LAB) from samples of raw (cow, goat) and traditional fermented milk product (nono).The assessed characteristics of LAB as indexed in Bergeys Manual of Determinative Bacteriology are cellular characteristic (Gram staining), growth at pH 4.5 and 9.6, growth in 5% NaCl, production of ammonia from arginine, tolerance to temperature 15 and 45oC, starch hydrolysis, and fermentation of sugars test. Fifty-five LAB were isolated and identified as Pediococcus acidilactici (15), Lactobacillus plantarum (29), Lactobacillus brevis (4), Lactobacillus casei (4), and Lactobacillus fermentum (3). Four species of the Lactobacillus isolated from nono samples were identified as Lactobacillus casei, Lactobacillus brevis, Lactobacillus plantarum and  Lactobacillus fermentum while Pediococcus acidilactici was isolated from raw cow and goat milk.  Lactobacillus plantarum was the dorminant organism with the highest frequency occurrence of 52.7% while Lactobacillus fermentum had the lowest (5.5%).  Lactobacillus species are normally found in fermented milk product which could be of great importance in food industry.