Impact of Ginger, Garlic Extracts, and Salt Concentration on the Microbial Load of Fermented Parkia biglobosa Seeds

Olatubosun Victor Ilesanmi; Ayobami Rachael Adesina; Adebowale D. Dada; Oluwatosin G. Oke

doi:10.5455/EJMID.20251202095709

Abstract
Aim: This study (2024) investigated the effects of Zingiber officinale (Ginger) and Allium sativum (Garlic) extracts, as well as salt concentration, on the microbial load and shelf stability of fermented Parkia biglobosa seeds (African locust bean). Methods: Fermented samples were treated with 5% (w/w) concentrations of Z. officinale extract, A. sativum extract, sodium chloride, and their combinations. The 5% (w/w) concentration was defined as 5 g of treatment agent per 100 g of fermented P. biglobosa seeds (wet weight basis). Microbial enumeration was performed using standard plate count methods over a 75-day storage period at ambient temperature (28 ± 2 °C), with sampling at 15-day intervals. Bacterial and fungal counts were determined as colony forming units per gram (CFU/g) and are also presented as log10 CFU/g. Statistical analysis was performed using one-way ANOVA with Tukey’s post-hoc test (p < 0.05). Results: Seven bacterial species from five genera (Bacillus, Staphylococcus, Lactiplantibacillus, Micrococcus, and Pediococcus) and five fungal genera (Saccharomyces, Mucor, Aspergillus, Alternaria, and Candida) were identified. Combined treatment with A. sativum and salt showed the lowest bacterial count (90 CFU/g; 1.95 log10 CFU/g) after 75 days, representing a 6.44 log10 reduction compared to control (2.48 × 108 CFU/g; 8.39 log10 CFU/g) (p < 0.001). Z. officinale demonstrated superior antifungal activity. Conclusion: The combined application of 5% (w/w) A. sativum, salt, and Z. officinale significantly extended the shelf stability of fermented P. biglobosa condiment by reducing microbial load throughout the 75-day storage period.

Key words: Microbial Load, Fermentation, parkia biglobosa seeds, Microorganisms, Food preservation