Professional Assessment of Mycotoxin Contamination in Stored Maize Grain in Borno State, North East Nigeria

Mycotoxin contamination of stored maize poses serious public health and food security risks in Borno State, where grain is stored in traditional structures for extended periods to bridge seasonal food gaps. Aflatoxins produced by Aspergillus flavus and A. parasiticus, and fumonisins produced by Fusarium verticillioides, are the mycotoxins of greatest concern in Nigerian maize storage systems. This professional study assessed the prevalence and levels of aflatoxin B1 and fumonisin B1 contamination in stored maize across 90 storage units in four districts of Borno State during 2023 and 2024. Grain samples were collected at 0, 3, 6, and 9 months post-harvest, and mycotoxin quantification performed using high-performance liquid chromatography. Aflatoxin B1 exceeded the European Union maximum tolerable level of 2 micrograms per kilogram in 48 percent of samples tested at the 6-month mark. Fumonisin B1 contamination above the 1000 micrograms per kilogram guideline was detected in 37 percent of samples at the same time point. Grain moisture content above 14 percent was the strongest predictor of mycotoxin accumulation across all storage systems. Metal silo storage with desiccant sachets was associated with significantly lower contamination levels compared to traditional clay pot and bag storage. The study recommends a mandatory grain moisture testing campaign before storage, subsidised metal silo access, and integration of mycotoxin awareness into health extension messaging in the North East zone. Keywords: mycotoxin, aflatoxin, maize, storage, Borno State.