Antimicrobial Effects of Lactic Acid Bacteria on Food-Borne Pathogens Isolated from Some Fruits Sold in Ibadan, Nigeria

Abstract

This study was conducted to determine the antimicrobial effect of Lactic acid bacteria on food-borne pathogens isolated from some fruits sold in Ibadan, Nigeria. Lactobacillus species isolated from healthy fruits include L. casei, L. brevis, L. desidosus, L. jenseni, Lactiplantibacillus plantarum and Fructilactobacillus spp. while Aeromonas hydrophylia, Enterobacter aerogene, Escherichia coli, Salmonella typhii, Shigella dysentriae, Pseudomonas fluorescens, Bacillus megaterium, Candida valida, Saccharomyces cerevisiae, Rhizopus stolonifer were isolated from spoilt fruits using pour plate technique and biochemical test. Gram-negative isolates were 100% resistant to Cefuroxime, Amoxycillin/Clauvulanate, and Ampicillin while 93.75% of the isolates were highly sensitive to Ofloxacin. Gram-positive isolates were 100% resistant to Cloxicillin and highly sensitive to Ofloxacin and Gentamycin using an antibiotic disc. Lactiplantibacillus plantarum had the highest amount of Lactic acid (5.6 g/l) while L. casei had the lowest yield (3.6 g/l) at 48 hours. L. casei had the highest amount of hydrogen peroxide (0.00036 g/l) while Lactiplantibacillus plantarum. and Fructilactobacillus spp. had the lowest yield (0.00021 g/l) at 48 hours. The highest amount of diacetyl (3.01 g/l) was produced by L. jenseni while the lowest amount was observed in L. brevis (0.43 g/l) at 48 hours. The maximum inhibitory activity was observed in L. brevis against B. megaterum with a diameter of 18mm zone of inhibition while the minimum activity by L. desidosus, L. jenseni, Fructilactobacillus spp. was observed against B. subtilis and Lactiplantibacillus plantarum against K. pneumoniae with diameter 8 mm zone of inhibition. The antimicrobial compounds produced by the Lactic Acid Bacterial had antimicrobial effects on food-borne pathogens.