Single and Mixed-Strain Starter Culture in Yoghurt Processing
L actic acid bacteria (LAB) were isolated from cowmilk yoghurt by culturing the milk on specific media and pure culture was obtained by sub-culturing. Preliminary identification of lactic acid bacteria was made on the basis of Gram-staining and catalase reaction followed by microscopic examination to observe cell arrangement and morphological characteristics. After incubation, individual colonies were selected and moved into sterile brooths (MRS or M17 medium for enrichment). The enriched bacteria were purified using streak plate technique. Gram positive and catalase negative cocci and bacilli colonies were stored in glycerol solution as lactic acid bacteria. Cowmilk yoghurt contained lactic acid producing bacteria, four bacterial strains were isolated, according to biochemical identification and were characterize as: Lactobacillus rhaminosus-2, Lactobacillus fermentum, Lactobacillus paracasei-2, and Lactobacillus licheniformis-2. The isolates were characterized on the basis of t...