MICROBIAL AND CHEMICAL RISK ASSESSMENT OF STREET-VENDED FOODS IN TERTIARY INSTITUTION ENVIRONMENTS IN SOUTHWEST NIGERIA: IMPLICATIONS FOR FOOD SAFETY AND PUBLIC HEALTH

Abstract

Street-vended foods constitute an essential component of the urban food supply chain in
developing countries, providing affordable, convenient, and readily accessible meals to millions
of consumers, particularly within tertiary institution environments. Despite their socioeconomic
significance, concerns regarding their microbiological and chemical safety continue to increase
because of poor hygienic practices, environmental pollution, inadequate regulatory oversight, and
limited food safety awareness among vendors. This study assessed the microbial and chemical
risks associated with street-vended foods sold within selected tertiary institutions in Southwest
Nigeria. A cross-sectional laboratory-based study was conducted using representative samples of
commonly consumed ready-to-eat foods collected from institutional environments. Microbial
quality was determined using standard microbiological techniques involving enumeration,
isolation, and biochemical identification of foodborne pathogens, while chemical analyses focused
on the determination of heavy metals and selected chemical contaminants using internationally
approved analytical procedures. Vendor hygiene practices and food handling behaviours were
simultaneously evaluated using structured observational checklists. Descriptive and inferential
statistical analyses were employed to determine contamination patterns and relationships between
food handling practices and food safety outcomes. The findings revealed considerable microbial
contamination of several food categories, with total viable bacterial counts, coliforms, and
pathogenic organisms exceeding internationally acceptable limits in a substantial proportion of
samples. Detectable concentrations of selected heavy metals were also identified, although
contamination levels varied according to food type and vending location. Poor personal hygiene,
inadequate storage conditions, repeated handling of ready-to-eat foods, and exposure to trafficrelated pollutants significantly contributed to elevated contamination risks (p < 0.05). The study
demonstrates that street-vended foods within tertiary institution environments present measurable
public health risks capable of increasing the burden of foodborne diseases among students and
staff. The integration of microbiological assessment, chemical risk evaluation, and behavioural
observation provides comprehensive evidence to support institutional food safety policies,
environmental health surveillance, vendor training programmes, and strengthened regulatory
enforcement.