Developing a Systems-Level Framework for Reducing Mycotoxin Contamination Along the Maize Value Chain in the Middle Belt of Nigeria

Mycotoxin contamination, particularly aflatoxin and fumonisin, in maize (Zea mays) poses a severe food safety and public health challenge in the Middle Belt region of Nigeria, where maize is a dietary staple and commercial crop. Effective mycotoxin management requires interventions across the entire value chain, yet existing approaches are fragmented and single-stage. This study develops an original systems-level framework for mycotoxin contamination reduction that integrates biological, engineering, and management interventions across the maize value chain in Benue, Nasarawa, Kogi, and Kwara States. The theoretical contribution is a causal loop diagram and system dynamics model of mycotoxin accumulation and intervention, identifying feedback loops and leverage points that determine the effectiveness of intervention combinations. The empirical component involves four years of longitudinal mycotoxin surveillance data from 240 farm households, 40 aggregators, and 20 processors combined with experimental evaluation of five intervention strategies: biological control using Aflasafe Nigeria, modified hermetic storage, ozone treatment in storage, solar decontamination of high-contamination stocks, and lactic acid fermentation for fumonisin reduction. Intervention effectiveness was quantified using the model and validated against observed contamination trajectories. The system dynamics model identified hermetic storage combined with biological control as the highest-leverage intervention pair, achieving an estimated 71 percent reduction in population-level aflatoxin exposure. The study represents the first systems-level analysis of mycotoxin management in Nigerian maize and provides a policy design tool for the Federal Ministry of Agriculture and international food safety organisations. Keywords: mycotoxin, aflatoxin, maize, systems dynamics, value chain Nigeria