Lactic Acid Bacterial Bacteriocins and Their Bioactive Properties Against Food Associated Antibiotic Resistant Bacteria

Abstract

Purpose: Incidence of food borne diseases and growing resistance of pathogens to classical antibiotics is a major concern in the food industry. Consequently, there is increasing demand for safe foods with less chemical additives but natural products which are not harmful to the consumers. Bacteriocins produced by lactic acid bacteria (LAB), is of interest because they are active in a nanomolar range, do not have toxic effects and are readily available in fermented food products.Methods: In this research, LAB were isolated from fufu, gari, kunu, nono and ogi using De Mann, Rogosa and Sharpe agar. Result: A total of 162 isolates were obtained from the food samples. Antimicrobial sensitivity test yielded positive result for 45 LAB isolates against Staphylococcus aureus ATCC 25923 while 52 LAB isolates inhibited the growth of Escherichia coli ATCC 25922. On confirmation of the bacteriocinogenic nature of the inhibitory substance, 4 of the LAB isolates displayed a remarkable degree of inhibition to Leuconostoc mesenteroides, Salmonella typhimurium and Bacillus cereus. Agar well diffusion assay was also performed using the cell-free supernatant (CFS) obtained from Lactobacillus fermentum strain NBRC15885, Lactobacillus fermentum strain CIP102980, Lactobacillus plantarum strain JCM1149 and Lactobacillus natensis strain LP33. The (CFS) was able to inhibit the growth of B. subtilis, Klebsiella pneumonia, S. typhimurium, S. aureus and E. coli which are foodborne pathogens.Conclusion: It therefore portends that the bacteriocins produced by the LAB isolated from these food products could act as probiotics for effective inhibition of the growth of antibiotic resistant foodborne pathogens.