Aflatoxin Contamination in Grains Sold at Selected Markets, Kaduna, Nigeria

Abstract

Grains marketed under open and poorly controlled storage conditions are highly 
susceptible to fungal colonization and subsequent aflatoxin contamination, with 
significant implications for food safety, public health, and economic valuation. This study 
quantitatively assessed aflatoxin contamination and associated mycobiota in three staple 
cereals—maize, millet, and sorghum—sourced from Kawo and Kasuwar Bacci markets in 
Kaduna between April and July 2025. Representative samples (300 g per grain type) were 
randomly procured from multiple vendors, aseptically packaged in sterile paper envelopes, 
and transported for laboratory analysis at the National Agency for Food and Drug 
Administration and Control (NAFDAC) facility. Quantification of total aflatoxins was 
conducted using a validated enzyme-linked immunosorbent assay (ELISA) protocol, while 
fungal isolation and enumeration were performed via standard culture-based techniques 
following surface sterilization. Microbiological analysis revealed that millet samples from 
Kawo market exhibited the highest fungal burden (3.0 × 10⁵ cfu/g), followed by sorghum 
(2.0 × 10⁵ cfu/g) and maize (1.2 × 10⁵ cfu/g). Similarly, at Kasuwar Bacci, millet recorded 
the highest load (1.7 × 10⁵ cfu/g), with maize (1.4 × 10⁵ cfu/g) and sorghum (1.2 × 10⁵ 
cfu/g) showing comparatively lower counts. Identified fungal taxa included Aspergillus 
flavus, Aspergillus niger, Penicillium spp., and Mucor spp., all of which are known for their 
toxigenic potential under favorable conditions. Total aflatoxin concentrations ranged 
from 2.418 to 2.676 µg/kg, with the maximum value observed in maize samples from 
Kasuwar Bacci market. Despite detectable fungal contamination, the relatively low 
aflatoxin levels indicate compliance with established permissible limits, suggesting that 
the grains remain within acceptable safety thresholds for human consumption.