Abstract:
The antibacterial activity of ethanol, hot water and cold water extracts of Allium cepa, Xylopia aethiopica and Piper guineense were determined against bacteria isolated from spoilt egusi soup and veterinary unit of the university. Antimicrobial testing was by both broth –dilution and agar diffusion methods. The spices tested, Allium cepa, Xylopia aethiopica and Piper guineense were extracted with cold, hot water and with ethanol. The ethanol extract of Piper guineense gave the highest yield of extract 4.8g (32%). The highest IZD (14.7±0.3mm) was achieved with hot water extract at concentration of 400mg/ml against Escherichia coli. The hot water extract also had activity against Bacillus sp (IZD= 12.7±0.6mm) isolated from spoilt egusi-soup. The Bacillus strain isolated from spoilt pepper-soup was not susceptible to the hot water extract and indeed any other extract even at the highest concentration. The most susceptible test organism was E.coli with IZD ranges of 12.0± 0.1mm (obtained from cold water extract of X. aethiopica at 400mg/ml) to 14.7±0.2mm (from hot water extract of Piper guineense at 400mg/ml). The least susceptible were Enterobacter sp and Proteus sp. which were only susceptible to cold water extract of A. cepa (IZD= 10.0± 0.2mm and 12.0±0.2mm both at 400mg/ml, respectively). Ethanol extracts showed no activity against any test organisms. Result show that the spices have potentials for use as food preservatives while still acting as food condiments.
