摘要：Isolation of lactic acid bacteria (LAB) from yoghurt, wara (cheese) and nono (fermented milk) was carried out. LAB were cultivated on lactic acid medium and were characterized based on colony morphology, cell morphology and biochemical tests. Out of fifteen samples analysed, thirteen (86.6%) harboured LAB. Nono had the highest LAB counts (9.8 x 106cfu/ml) while yoghurt had the lowest LAB counts (3.1x106cfu/ml). The lactic acid bacterial isolates were identified as Lactobacillus bulgaricus (31.6%), Lactobacillus lactis (15.8%), Lactobacillus acidophilus (10.5%), Streptococcus thermophilus (15.8%), Strectococcus cremoris (10.5%), Lactococcus lactis (15.8%), Pediococcus halophilus (5.3%) and Pediococcus cerevisiae (5.3.%). The presence of these organisms in fermented milk products and other food products will enhance preservation ( shelf life extension) of the products. The LAB were screened for potential to produce bacteriocins in De Man Rogosa Sharpe (MRS) broth. Of the thirty four LAB screened for bacteriocin production, nineteen (55.9%) were potential bacteriocin producers and they included strains of Lactobacillus bulgaricus, Lactobacillus lactis, Lactobacillus acidophilus, Lactococcus lactis, Streptococcus cremoris, Pediococcus halophilus and Pedioccus cerevisiae. Lactobacillus bulgaricus had the highest bacteriocin activity of 6000 Au/ml against all the indicator microorganisms used while Pediococcus cerevisiae had the least bacteriocin activity of 4800 Au/ml against salmonella sp and Bacillus sp.The presence of LAB in foods can cause shelf life elongation and safety of the food products
关键词：lactic acid bacteria; bacteriocins; fermented milk; De Man Rogosa Sharpe broth; lactic acid medium
