Assessement of Microbiological Quality and Toxic Heavy Metals in Raw Chicken Eggs Sold in Kano Metropolis

Student: Usman Hamisu Garba (Project, 2025)
Department of Animal Science
Bayero University, Kano, Kano State


Abstract

This study aimed to determine the concentrations of selected toxic heavy metals (lead, cadmium, and chromium) and assess the microbiological quality of raw chicken eggs sold in Kano Metropolis. A total of 9 raw chicken eggs were randomly collected from egg selling points across three locations—Kano Municipal, Nassarawa, and Kumbotso—and subjected to laboratory analysis at Bayero University, Kano. Heavy metal concentrations were determined using atomic absorption spectrophotometry (AAS), while microbiological quality was evaluated using microbiological enumeration, biochemical characterization, and antibiotic susceptibility testing. The experimental design was a completely randomized design (CRD), data generated were analyzed using ANOVA with JMP version 17.0 and significantly different means separated with Tukey HSD. The findings revealed significant contamination with lead (Pb) across all samples (ranging from 26.18–40.07 mg/kg), notably exceeding international safety limits, with the highest concentration observed in the Nassarawa area, suggesting environmental contamination possibly from industrial and vehicular sources. Microbiological analysis indicated minimal coliform contamination but identified pathogenic bacteria such as Escherichia coli, Staphylococcus aureus, Proteus spp., and Streptococcus spp. Some isolates, particularly Escherichia coli, exhibited multidrug resistance, posing an additional public health risk. The study concludes that serious concerns regarding both heavy metal, microbiological contamination and antimicrobial resistance in raw eggs sold in Kano metropolis. Regulatory bodies such as NAFDAC and SON strictly enforce guidelines limiting heavy metal contamination in poultry eggs. Routine monitoring and assessment of eggs be conducted by food safety and public health authorities in Kano Metropolis, and antibiotic use in poultry farming should be strictly regulated to combat antimicrobial resistance. Future studies should use larger sample sizes to provide more comprehensive surveillance data.

Keywords
heavy metals eggs chicken