Empirical Investigation of the Relationship Between Post-Harvest Handling Practices and Aflatoxin Contamination in Groundnuts in Katsina State

Aflatoxin contamination in groundnut is a persistent food safety challenge in northern Nigeria with documented links to hepatocellular carcinoma, child stunting, and immunosuppression. While the environmental and biological determinants of aflatoxin production are well established, the specific post-harvest handling practices that modulate contamination levels in Katsina State, North West Nigeria, have not been empirically characterised at scale. This study investigates the quantitative relationship between specific post-harvest handling variables and total aflatoxin B1 levels in groundnuts from 120 smallholder farms and 30 storage facilities across three local government areas in Katsina. Variables assessed include harvest timing, curing method and duration, pod moisture content at storage entry, storage structure type, bag material, and duration of storage. Aflatoxin B1 was quantified by enzyme-linked immunosorbent assay on composite samples collected at six weeks and twelve weeks after storage entry. Multivariate regression analysis identified pod moisture content at storage entry and storage structure type as the strongest predictors of aflatoxin B1 level, together explaining 62 percent of the total variance. Pods stored at moisture above 10 percent wet basis in unventilated sacks had a 4.7-fold higher probability of exceeding the European Union limit of 2 micrograms per kilogram compared to pods stored at below 8 percent moisture in ventilated stores. The study draws on recent aflatoxin management literature and contributes evidence for targeting post-harvest interventions in the groundnut value chain. Keywords: aflatoxin, groundnut, post-harvest handling, Katsina State, food safety