Carbohydrate Fermentation Profile and Physiological Studies of Lactic Acid Bacteria from Native Raw Cow Milk

Abstract

The aim of this study was to identify and evaluate the physiological studies of lactic acid bacteria from native raw cow milk. Cow milk samples were collected purposively from four different locations in Ibadan. The proximate analysis, pH and acidity of the milk samples were examined using standard procedures. Lactic acid bacteria (LAB) were isolated, characterized, and identified using both morphological, biochemical test, and Analytical profile index (API) system. The identified LAB were subjected to various physiological conditions such as growth at different temperature (15, 30, 45°C), pH (4, 6, 8) and NaCl concerntrations (4, 6, and 8%).The heterotrophic counts ranged between 3.1 ×107to 4.2 ×107CFU/mL and lactic acid bacteria counts ranged from 2.2× 107 to 3.8 × 107 CFU/mL. Thirty-five LAB isolates were randomly picked and identified as Lactobacillus (57.15%), Streptococcus (14.29%), Leuconostoc (8.57%), Pediococcus (8.57%), Lactococcus (5.71%) and Enterococcus (5.71%). The LAB isolates were further identified as Lactobacillus plantarum, Leuconostoc mesenteriodes, Lactococcus lactis, Lactobacillus acidiophilus and Lactobacillus bulgaricus based on API 50 test kit, and were able to grow at different physiological paramaters. This study shows that Lactobacillus strains isolated from raw cow milk had better physiological attributes. These LAB could be recommended for further assessment such as evaluation of probiotic potential properties and genomic analysis.