Investigation of Bacteria and Fungi Associated with Onion (Allium cepa) Bulbs Rot Purchased from Markets in Makurdi, Central Nigeria

Abstract

Onion (Allium cepa) sometimes referred to as the bulb onion and utilized as a vegetable is the most extensively cultivated species of the genus Allium. This study evaluated the bacteria and fungi linked to the rot of onion bulbs purchased from markets within the Makurdi metropolis. Samples were analyzed using two dilution factors (10³ and 10⁵) for each sample isolation. All other relevant tests carried out adopted standard microbiological procedures for bacteria and fungi isolation, characterization, and identification. The percentage prevalence of bacterial isolates was; Escherichia coli (33.33%), Pseudomonas spp (30%), Staphylococcus spp (20%), and Bacillus spp (16.67%), while fungal isolates were; Aspergillus spp (43.33%), Rhizopus spp (26.67%), Mucor spp (16.67%), and Saccharomyces cerevisiae (13.33%). The average bacterial count ranged between 20.8 x 10⁴ and 22.4 x 10⁶ CFU/ml, while the fungal counts varied between 0.1 x 10⁴ and 1.0 x 10⁶ CFU/ml. Since these microorganisms are also known to produce toxins harmful to human and animal health, having the right mycological knowledge, storage options, and handling techniques would help to prevent onion bulbs from rotting and subsequently deteriorating, ensuring that they are available to society throughout the year.