Antimicrobial Activity of Xylopia aethiopica Extract on Microorganisms Associated with the Spoilage of Vegetables in Mile 3 Market, Port Harcourt Nigeria

Abstract

With increasing demand for natural preservatives, this study explores the effectiveness of Xylopia aethiopica extracts in reducing vegetable spoilage. The aim was to evaluate these extracts' potential to inhibit spoilage microorganisms, determine the most effective concentration for preservation, and assess their impact on sensory qualities. Vegetables (onions, tomatoes, and carrots) were purchased from vendors at Mile 3 Market, Port Harcourt, and transported to a microbiological laboratory for analysis. The vegetable samples were treated with ethanol and aqueous extracts of Xylopia aethiopica at concentrations of 10%, 20%, and 30% (w/v). For microbial analysis, treated and control vegetable samples were homogenized, cultured on nutrient agar for bacteria and potato dextrose agar for fungi, and incubated at optimal conditions for colony formation. Enumeration of bacterial and fungal colonies was conducted periodically over 14 days. Microorganisms isolated included Bacillus cereus, Pseudomonas aeruginosa, Aspergillus niger, and Penicillium spp. Phytochemical analysis revealed that the ethanol extract had higher concentrations of bioactive compounds, including alkaloids (2.5%), flavonoids (3.1%), saponins (1.4%), tannins (2.2%), phenolics (4.3%), and glycosides (1.1%), compared to the aqueous extract. Results showed that the 30% ethanol extract was the most effective, significantly reducing bacterial and fungal growth compared to the control and other treatments. ANOVA analysis confirmed significant reductions in microbial counts in treated vegetables (p < 0.05). Sensory evaluation revealed that the extracts, particularly the 30% ethanol extract, did not negatively affect the vegetables' taste, smell, or appearance. This study demonstrates the potential of Xylopia aethiopica as an effective natural preservative, offering a promising alternative to synthetic preservatives. Future research should focus on long-term effects, broader applications, and consumer acceptance for practical implementation.