Antimicrobial activity of ethanolic extracts of Xylopia aethiopica , Aframomum melegueta and Piper guineense fruits were assayed against fourteen (14) microorganisms commonly associated with food poisoning and/or food spoilage. The microorganisms were Bacillus subtilis IAM1069, Bacillus cereus IFO 13494, Staphylococcus aureus FDA 209p, Escherichia coli NRIC 1023, Salmonella typhimurium IFO12529, Lactobacillus plantarum IAM 1041, Pediococcus acidilactici -M, Leuconostoc mesenteroides - M, Lactobacillus casei TISTR390, Saccharomyces cerevisiae OC-2, Hansenula anomala IFO 0140 (p), Pichia memb.IFO 0128, Penicillium funiclosum NBRC 6345 and Candida species. All the plant extracts exhibited selective antimicrobial activities on the test organisms. X. aethiopica extract exhibited the highest antimicrobial activity on the organisms with a minimum inhibitory concentration (MIC) of 50 ppm on Bacillus species and S. aureus. S. cerevisiae (MIC = 300 ppm), P. funiclosum NBRC 6345 and L. mesenteroides (MIC = 500 ppm) were also susceptible to X. aethiopica fruit extract but the MIC values for the other tested microorganisms were higher than 1000 ppm. This was followed by A. melegueta fruit extract with MIC of 100 ppm for B. cereus and S. aureus . Although P. guineense fruit extract inhibited the growth of B. cereus and S. aureus (MIC = 300 ppm); and B. subtilis (MIC = 1000), the MIC for the other microorganisms were higher than 5000 ppm. On the whole, all the plant extracts exhibited the least antimicrobial activities on Lactobacilli and fungi species. X. aethiopica fruit extract was used to preserve fresh orange juice. The ability of 100 and 1000 ppm extract to preserve the orange juice was significantly greater (p<0.05) than 50 ppm. The microbial concentration in orange juice containing 100 ppm of X. aethiopica extract was 4 cfu/mL after 28 days of storage at room temperature. Keywords: Food spoilage, food poisoning, microorganisms, spices, ethanolic extract, natural preservatives, orange juice African Journal of Biotechnology Vol. 12(16), pp. 1993-1998