The Biopreservative Potential of Lactic Acid Bacteria Isolated from Mouse Gut Against some Food Spoilage Organism

Lactic Acid Bacteria from the Gut of Mouse

Abstract

The use of the Lactic acid bacteria and their extra cellular proteinous substances known as bacteriocin in the food processing and preservation industries are gaining more attention. The cells and secondary metabolites from these bacteria provide a biological food preservative suitable as an alternative to the use of chemical in extending food shelf life.  The present research was aimed at examining the potential of crude bacteriocin from lactic acid bacteria (LAB) isolated from the gut of mouse as a biopreservative against the commonly encountered food spoilage bacteria. Using standard microbiological methods, LABs were isolated from the gut of a mouse on De Mann Raggussa Agar, characterized and identified. Crude bacteriocin was obtained from broth culture of the isolates and tested for antibacterial activity against Pseudomonas aeruginosa, Escherichia coli, Bacillus magaterium, Bacillus cereus, and Staphylococcus aureus using agar well diffusion method. Four species of Gram positive LAB were obtained, three of which were Lactobacillus species 1, 3 and 4 while one was a Lactococcus species.  Crude bacteriocin from the Lactococcus species was the most effective against all the tested bacteria except B. megaterium, crude bacteriocin from Lactobacillus species 1and 3 were not effective against E. coli and B. megaterium while the crude bacteriocin from Lactobacillus species 4 was active against only S. aureus. S. aureus was the most sensitive to the crude bacteriocins with an average zone of inhibition of 16.50 mm followed by B. cereus (14.00 mm) and P. aeruginosa (13.50 mm), the least was in E. coli while B. megaterium (0.00 mm) was the most resistant in all. This study consolidates the claim that bacteriocins from LAB can exercise biorprotective potential on food through inhibiting the growth of food spoilage bacteria.

KEYNOTES: Lactic acid bacteria, Biopreservative, Bacteriocins, Lactobacillus, Lactococcus, Food spoilage bacteria.