Abstract

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The present study evaluates the in-vitro antibacterial activities of lactic acid bacteria (LAB) isolated from two fermented cereal products - ogi and kunun-zaki, against organisms implicated in gastrointestinal tract infections. A total of fifteen (15) LAB strains with 5 each from white maize agi, yellow maize ogi, and kunun-zaki were isolated and characterized. The LAB strains were tested against 5 clinical pathogens. The highest zone of inhibition against Shigella (20.0mm) was shown by Lactobacillus helveticus YM0007 and L. casei YM2434 bothfrom yellow maize ogi while the lowest zone of 1.0mm was observed in L. lactis KN49 from kunun-zaki. Against Salmonella typhi, the highest zone of inhibition of 22.5mm was shown by L. fermentum WM4825 from white maize while the lowest zone of 1.0mm was observed in L. plantarum KN56. L. brevis WM4832 had the highest zone of 25.0mm against Escherichia coli while the lowest zone of 1.0mm was observed in L. lactis KN49 and L. brevis KN46. The highest zone of inhibition (20.0mm) against Enterococcus faecalis was observed in L. helveticus YM0007 while the lowest zone of 5.0mm was shown by L. casei KN39. Against Klebsiella sp., the highest zone of inhibition of 27.5mm was shown by L. casei WM4826 while the lowest zone of 4.0mm was observed in L. casei KN39. The highest production of lactic acid was observed in L. bulgaricus KN46. L. plantarum KN56 produced the highest amount of hydrogen peroxide while the highest amount of diacetyl was produced by L. lactis KN49. This study suggests that lactic acid bacteria found in ogi and kunun-zaki -coutd be useful in ameliorating gastrointestinal trtict infections.

Keywords: Antibacterial activity, Gastrointestinal tract infections, Kunun-zaki, Lactic acid bacteria, Ogi.