Prevalence and Environmental Determinants of Aflatoxin Contamination in Maize Sold in Open Markets Across Nasarawa State, Nigeria

This study evaluated the prevalence of aflatoxins (AFB1, AFB2, AFG1, and AFG2) in maize sold across 13 Local Government Areas (LGAs) in Nasarawa State, Nigeria, and examined how environmental factors contribute to fungal growth and mycotoxin production. Maize samples (130) were subjected to total heterotrophic fungal count (THFC) analysis using standard microbiological methods, while aflatoxin levels were measured using thin-layer chromatography (TLC) combined with densitometry. Statistical methods, including analysis of variance (ANOVA) and regression modeling, were utilized to clarify spatial contamination trends and identify environmental variables that could predict contamination. The findings revealed significant aflatoxin contamination, with 85.4% of samples surpassing the 20-ppb safety limit set by the Standards Organisation of Nigeria (SON). Aspergillus flavus, the main producer of aflatoxin B1, was found in 94% of the samples, followed by Fusarium verticillioides (71%) and Aspergillus niger (59%). Regression analysis showed a strong correlation (r = 0.710, P<0.001) between fungal load and AFB1 levels, with humidity explaining 41.1% of the variability in THFC. The highest AFB1 concentration (137.10 ± 15.10 ppb) was found in Doma, while Lafia showed consistently lower contamination levels, likely due to better post-harvest handling practices. This study underscores the urgent need for targeted interventions to reduce aflatoxin contamination, such as rapid drying, hermetic storage systems, and educating farmers on preventing fungal growth. It also recommends implementing aflatoxin surveillance programs and researching resistant maize varieties to improve food safety and public health in Nasarawa State.