Detection of Aflatoxin Contamination in Stored Groundnuts from Selected Markets in Katsina State

Aflatoxins produced by Aspergillus species in stored groundnuts represent a significant food safety and public health risk, particularly in hot and humid storage conditions common in northern Nigerian markets. This study investigates aflatoxin contamination levels in groundnut samples purchased from five markets in Katsina State. Fifty groundnut samples were collected, including both shelled and unshelled types, from Katsina, Daura, Funtua, Malumfashi, and Mani markets. Total aflatoxin and aflatoxin B1 concentrations were determined by competitive enzyme-linked immunosorbent assay (ELISA) using a validated commercial kit. Moisture content was determined gravimetrically. Fungal isolation was performed on potato dextrose agar, and Aspergillus species were identified by morphological characterization. Results show that forty-two of fifty samples (84%) contained detectable aflatoxin. Aflatoxin B1 exceeded the European Union maximum threshold of 2 micrograms per kilogram in 58 percent of samples and exceeded the Nigerian NAFDAC guideline of 10 micrograms per kilogram in 34 percent of samples. Shelled groundnuts stored in open market conditions showed higher contamination levels than unshelled samples. Aspergillus flavus and Aspergillus parasiticus were the predominant species isolated. Moisture content above 9 percent was significantly associated with higher aflatoxin levels. The high prevalence of aflatoxin contamination in Katsina markets represents a serious health hazard and a barrier to export quality. The study recommends improved storage infrastructure and aflatoxin awareness training for groundnut traders. Keywords: aflatoxin, groundnuts, Aspergillus, food safety, Katsina State.