Role of ginger extract in microbial inhibition and sensory enhancement of stored plant-based drinks: A study on soymilk and Zobo

Plant-based beverages like soymilk and zobo are increasingly popular but highly susceptible to microbial spoilage, particularly in Nigeria, where cold chain infrastructure is inconsistent. This study investigated the dual effects of ginger extract on microbial inhibition and sensory enhancement of these beverages during 6 h ambient storage. Fresh soymilk and zobo samples were collected from local vendors and treated with 2% and 5% ginger extract concentrations. Microbiological analysis, pH determination, and sensory evaluation using a 9-point hedonic scale were conducted on fresh and stored samples. Initial microbial counts revealed high total viable counts (4.20×10⁵ to 5.20×10⁵ CFU/ml) and total coliform counts (8.40×10⁵ to 1.04×10⁶ CFU/ml), indicating contamination during production. While 2% ginger showed inconsistent antimicrobial effects, 5% ginger significantly reduced microbial loads, with zobo sample ZBF showing the lowest counts (1.50×10⁵ CFU/ml TVC). Biochemical characterization identified pathogenic organisms including Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Sensory evaluation revealed that 5% ginger enhanced zobo acceptability but compromised soymilk palatability due to overpowering flavor. The study demonstrates that ginger extract at 5% concentration provides effective antimicrobial activity, particularly in acidic matrices, offering a practical natural preservation strategy for resource-constrained environments where consistent cold storage is of concern.