Abstract:
Biopreservation systems in foods are gaining popularity in food industries. Bacteriocins,
an antimicrobial peptide produced by lactic acid bacteria, is considered as safe
additives. Therefore, this study aimed to isolate bacteriocin-producing lactic acid
bacteria from selected natural fermented food products with wide spectrum
antimicrobial activity. Lactic acid bacteria were isolated from yoghurt, curd, dosa batter,
idli batter and rice batter using de Man, Rogosa and Sharpe (MS) agar and incubated at
room temperature (30±2 °C) for 24-72 h aerobically and anaerobically. Agar well
diffusion method was employed to detect the antimicrobial activity of isolates against
food spoilage organisms (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli,
Pseudomonas aeruginosa, Klebsiella pneumonia, Serratia marcescens, Salmonella sp.,
Proteus sp., Micrococcus sp., and Bacillus sp.). Antimicrobial activity screening by agar
well diffusion assay showed that isolate C3 from curd sample inhibited wide range of
bacterial species. Therefore, that wide spectrum bacterium was subjected to diverse
cultural, biochemical and morphological studies such as colony morphology, gram
staining, catalase test and motility test and identified as Lactobacillus sp. Further studies
are under way to purify and characterize the bacteriocin and to confirm whether the
selected strain could be used to produce bacteriocin to preserve the food at industrial
level.
