Determination of Aflatoxin Contamination in Groundnut Samples from Markets in Kano State

Aflatoxins, secondary metabolites produced by Aspergillus species, pose significant food safety and public health risks when present in staple crops such as groundnuts. Nigeria is among the world's largest groundnut producers, yet mycotoxin contamination in locally marketed groundnut products is a recognised but incompletely documented problem. This study determined aflatoxin levels in groundnut samples collected from five major markets in Kano State. Forty samples each of raw, roasted, and groundnut paste were collected, representing a total of 120 samples. Aflatoxin extraction was performed using acetonitrile-water solution, and quantification was carried out using a competitive enzyme-linked immunosorbent assay kit validated against high-performance liquid chromatography. Results indicated that 68 percent of raw samples contained detectable aflatoxins, with total aflatoxin concentrations ranging from below the limit of detection to 92 micrograms per kilogram. The EU maximum limit of 4 micrograms per kilogram for aflatoxin B1 was exceeded in 41 percent of raw samples and 28 percent of roasted samples. Aflatoxin levels in groundnut paste were generally lower than in raw samples, possibly due to dilution effects during processing. Moisture content was positively correlated with aflatoxin concentration, consistent with the role of moisture in supporting fungal growth. The findings highlight a significant food safety risk in Kano groundnut markets and recommend adoption of hermetic storage technologies, post-harvest drying protocols, and routine aflatoxin testing as part of groundnut marketing regulations.

Keywords: aflatoxin, groundnut, ELISA, food safety, Kano State