Quantification and Risk Assessment of Mycotoxin Contamination in Groundnuts Stored Under Traditional Conditions in Kano State

Groundnut is a major oilseed crop and dietary protein source in North West Nigeria, and mycotoxin contamination, particularly aflatoxins, poses severe food safety and public health risks under tropical storage conditions. This study quantifies aflatoxin B1, B2, G1, and G2, ochratoxin A, and fumonisin levels in groundnut samples stored under traditional on-farm storage systems including clay pots, jute sacks, and polyethylene bags in Kano State. Sampling was conducted at zero, three, and six months post-harvest from 36 farmers across three agro-ecological zones. Mycotoxins were extracted by immunoaffinity column clean-up and quantified by high-performance liquid chromatography with fluorescence detection for aflatoxins and ochratoxin A, and enzyme-linked immunosorbent assay for fumonisins. Moisture content, water activity, and fungal identification by morphological and molecular methods were performed in parallel. Results show that aflatoxin B1 concentrations in jute sack-stored groundnuts reached 78 micrograms per kilogram after six months, greatly exceeding the EU maximum of 2 micrograms per kilogram and the Nigerian standard of 4 micrograms per kilogram for aflatoxin B1. Water activity above 0.70 was the strongest predictor of aflatoxin escalation, with Aspergillus flavus as the dominant producer. Clay pot storage consistently produced the lowest moisture retention and lowest mycotoxin accumulation. Probabilistic dietary risk assessment indicates that children under five consuming aflatoxin-contaminated groundnut paste face hepatocellular carcinoma risk exceeding acceptable limits. Practical hermetic storage recommendations are derived. Keywords: aflatoxins, mycotoxins, groundnut, Kano State, food safety