Microbiological Evaluation of Microbes Associated with the Deterioration of Banana Sold at Rumuokoro Market Port Harcourt, Rivers State

Banana (Musa spp.), a nutritionally valuable staple fruit, is highly perishable and vulnerable to postharvest microbial deterioration, particularly in informal markets lacking cold chains and hygienic handling. This study investigated the microbial profile and contamination dynamics of deteriorated bananas sold at Rumuokoro Market, Port Harcourt, Rivers State, Nigeria. Twenty banana samples were purchased from four different points at the market and subjected to standard microbiological assays. Total Heterotrophic Bacterial Counts (THBC) ranged from 3.5 × 10⁶ to 9.8 × 10⁶ CFU/g, while Total Fungal Counts (TFC) varied from 2.5 × 10⁴ to 4.2 × 10⁴ CFU/g both exceeding international safety thresholds established by the ICMSF. The most prevalent bacterial species were Staphylococcus spp. (53.3%), Streptococcus spp. (26.7%), and Escherichia coli (20.0%), reflecting contamination via human handling and possible fecal exposure. Fungal isolates included Fusarium spp. (38.4%), Aspergillus fumigatus, A. flavus, Mucor, Candida, and Rhizopus, with several known mycotoxin producers posing significant food safety risks. Spatial analysis revealed variable microbial burdens, with Point B exhibiting the highest contamination levels and Point A showing the greatest fungal diversity. These findings underscore the dual-pathway contamination model in open-air markets comprising both anthropogenic and environmental routes and highlight systemic lapses in postharvest handling, storage, and vendor hygiene. The presence of toxigenic fungi such as Fusarium and Aspergillus raises public health concerns due to the risk of chronic mycotoxin exposure. This study advocates for urgent implementation of Good Agricultural Practices (GAP), Good Hygiene Practices (GHP), and Hazard Analysis and Critical Control Points (HACCP) protocols. Additionally, the integration of microbial surveillance and targeted mycotoxin mitigation strategies is imperative to ensure food safety and consumer protection in resource-constrained urban produce markets.