Antimicrobial Activity of Moringa oleifera Leaf against Isolates of Beef Offal

Abstract

This study was designed to evaluate the antimicrobial potentials of ethanol and aqueous extracts of Moringa oleifera against microorganisms isolated from beef offal. The beef offal samples (liver, kidney and intestine) were purchased from an abattoir in Port Harcourt while the Moringa oleifera leaves were harvested from the farm, Rivers State University of Science and Technology, Port Harcourt. Plating was done using the spread plate method while test for inhibitory potential was done using disc diffusion method. Six species of bacteria (Bacillus cereus, Staphylococcus aureus, Escherichia coli, Streptocccus spp, Pseudomonas aeruginosa and Proteus vulgaris) and two mould species (Rhizopus spp and Mucor spp) were identified. Antimicrobial potentials of the ethanol and aqueous extracts of M. oleifera on isolates were tested at various concentrations (50, 100, 200 and 400 mgml-1). Ethanol extract of M. oleifera showed strong antimicrobial activity and concentration dependent inhibitory effect on beef offal isolates while the aqueous extract was ineffective on test bacteria isolates. At a concentration of 400 mg/ml, zones of inhibition recorded were highest with ethanol extracts for Staphylococcus aureus (14.00±0.6 mm), Bacillus cereus(13.00±0.1 mm) and Proteus vulgaris (12.00±0.4 mm). Minimum Inhibitory Concentration (MIC) was at 200 mg ml-1 for ethanol extract and 400 mg ml-1 for aqueous extract. The result of this study showed that M. oleifera is a potential source of antimicrobial agent against some pathogenic bacteria implicated in beef offal’s spoilage. The study recommends further research to be carried out on other extractive techniques since different extractive techniques may correspond to different antimicrobial effectiveness.