A Comprehensive Risk Assessment Framework for Foodborne Pathogen Hazards in Nigeria’s Informal Meat Sector

Nigeria's informal meat sector supplies the majority of animal protein to urban and peri-urban populations yet operates largely outside formal food safety regulatory oversight, creating a complex hazard landscape that lacks systematic risk characterization. This study developed and applied a comprehensive quantitative microbial risk assessment framework for foodborne pathogens in Nigeria's informal meat sector, using Lagos and Kano as primary study sites. Using a stochastic farm-to-fork risk assessment model, contamination data were collected at five critical points including farm, transit, abattoir, retail, and consumer preparation. Pathogens targeted included Salmonella Typhimurium, E. coli O157:H7, and Campylobacter jejuni. Monte Carlo simulation was used to propagate uncertainty and variability. Consumer exposure was estimated using dietary survey data from 1,000 urban households. Risk characterization estimated annual probability of illness per serving for each pathogen and identified the most sensitive control points. E. coli O157:H7 had the highest estimated annual illness probability at 3.1 per 1,000 servings. Evisceration in abattoirs and retail temperature abuse were identified as dominant risk contributors in sensitivity analysis. The study provides the first integrated quantitative microbial risk assessment framework contextualised for Nigeria's informal meat sector, filling a critical knowledge gap in domestic food safety risk governance. The proposed framework offers a tool for priority-setting in food safety investment decisions and regulatory design. Keywords: quantitative microbial risk assessment, informal meat sector, foodborne pathogens, Nigeria, food safety framework