Food Contamination and Safety in Nigeria: A Systematic Synthesis of Heavy Metals, Microbial Pathogens, and Health Risk Metrics

Abstract

ABSTRACT Food safety remains a critical challenge in Nigeria due to rapid urbanization and weak regulatory enforcement. This systematic review synthesizes empirical evidence from 2015 to 2025 to characterize food contaminant profiles and associated human health risks in Nigeria. Following PRISMA guidelines, a systematic search was conducted across five electronic databases. Analytical studies reporting quantitative data on chemical and biological contaminants in Nigerian food matrices were included. Risk of bias was assessed using a modified tool for cross‐sectional analytical studies. Forty‐one studies met the inclusion criteria. Contaminants included microbial hazards (43.9%), heavy metals (26.8%), pesticides (12.2%), and organic chemical pollutants. Heavy metal studies reported exceedances of FAO/WHO limits, with chromium and nickel driving cancer risks above the safety threshold. Mycotoxin (aflatoxin) contamination was often reported in artisanal and poorly stored foods, with levels more than threefold above regulatory limits. Ready‐to‐eat foods exhibited significant microbial loads, with a high prevalence of multidrug‐resistant pathogens. Nigerian consumers face a “dual burden” of chronic chemical exposure and acute microbial hazards. Urgent policy interventions are required to strengthen market surveillance, enforce antimicrobial stewardship in agriculture, and develop targeted risk communication for vulnerable subpopulations, particularly children.