Determination of Aflatoxin Contamination in Peanut Butter and Groundnut Products Sold in Zaria Markets, Kaduna State

Aflatoxins are mycotoxins produced primarily by Aspergillus flavus and A. parasiticus under warm, humid storage conditions. Groundnuts and their processed products are among the most susceptible commodities to aflatoxin contamination in Nigeria, where groundnut cultivation and consumption are particularly significant in the North West geopolitical zone. This study determined aflatoxin B1 and total aflatoxin concentrations in ten peanut butter brands and eight raw groundnut samples purchased from markets in Zaria, Kaduna State. Aflatoxins were extracted by immunoaffinity column clean-up and quantified by HPLC with fluorescence detection, with post-column photochemical derivatisation for enhanced sensitivity. Results were compared against NAFDAC and EU limits of 10 and 4 micrograms per kilogram respectively for total aflatoxins in food. Aflatoxin B1 was detected in 78% of all samples. Three peanut butter brands and four raw groundnut samples exceeded the EU total aflatoxin limit of 4 micrograms per kilogram. One raw groundnut sample contained total aflatoxins of 82 micrograms per kilogram, substantially above all regulatory limits. Locally roasted peanut butter showed lower contamination than commercially processed brands, contrary to expectation, suggesting post-processing contamination during packaging in some commercial products. These findings indicate a significant aflatoxin safety risk in groundnut products in Zaria and highlight the need for robust post-harvest handling guidelines and product-level surveillance in Kaduna State markets. Keywords: aflatoxin, groundnut, HPLC, Zaria, food safety.