Impact of storage practices on the quality and safety of maize in Kebbi State, Nigeria

Maize (Zea mays L.) is a key staple crop in Nigeria, yet postharvest storage practices significantly influence its quality and safety. This study evaluated the impact of storage methods on moisture content, microbial contamination, and aflatoxin levels in maize stored by farmers and traders in Kebbi State, Nigeria. A descriptive cross-sectional design was employed, integrating structured surveys, laboratory analyses, and statistical evaluation. Polypropylene bags were the most commonly used method, accounting for 30%, followed by granaries (26%), and traditional cribs (20%). Moisture content varied significantly (p < 0.05) across methods, with underground pits (17.0 ± 1.0%) and traditional cribs (16.2 ± 0.8%) showing the highest levels, whereas metal silos (12.5 ± 0.5%) and plastic containers (13.8 ± 0.7%) maintained the lowest. Total bacterial and fungal counts were highest in underground pits and traditional cribs and lowest in metal silos and plastic containers. Fungal species isolated included Aspergillus flavus, A. niger, A. fumigatus, Fusarium moniliforme, and F. graminearum, with prevalence correlating to storage conditions. Aflatoxin B1 was detected in 78–88% of maize samples, with the highest mean concentration in Yawuri (45.51 ± 96.31 μg/kg). Total aflatoxin levels varied significantly among locations (p < 0.05), indicating that storage practices directly influence mycotoxin accumulation. Findings highlight that traditional storage methods predispose maize to microbial proliferation and aflatoxin contamination, whereas modern systems, such as metal silos and sealed plastic containers, effectively preserve grain quality. The study underscores the need for improved storage technologies, proper drying, and stakeholder education to enhance maize safety, reduce postharvest losses, and strengthen food security in Kebbi State.