MICROBIOLOGICAL QUALITY AND ANTIMICROBIAL RESISTANCE PROFILES OF STREET-VENDED AWARA AND WAINA IN KADUNA STATE, NIGERIA

Abstract

Background: Street-vended awara (soybean curd) and waina (fermented rice cake) are widely

consumed ready-to-eat (RTE) foods in Kaduna State, Nigeria, whose microbiological safety remains

poorly characterized. Informal vending conditions and the escalating spread of antimicrobial

resistance (AMR), including extended-spectrum beta-lactamase (ESBL)-producing

Enterobacteriaceae, pose significant One Health concerns.

Objective: To assess the bacteriological quality of street-vended awara and waina, compare microbial

loads and species distribution between food types, evaluate temporal contamination patterns, and

characterize antimicrobial resistance profiles including ESBL production.

Methods: Forty samples (awara, n = 20; waina, n = 20) were collected aseptically from 10 vendors

across five markets at morning (07:00–09:00 h) and evening (16:00–18:00 h) time points. Total viable

counts were determined by pour-plate on nutrient agar. S. aureus, K. pneumoniae, P. aeruginosa, and

1. coli were isolated on selective media and identified biochemically. Antimicrobial susceptibility

testing was performed by Kirby–Bauer disc diffusion (amoxicillin, ciprofloxacin, gentamicin,

ceftazidime); multidrug resistance (MDR) was defined as resistance to ≥3 antimicrobial classes.

ESBL production was confirmed by double-disc synergy test. Data were analysed using Wilcoxon

rank-sum and Pearson's chi-square tests in R (v4.3.3).

Results: All 40 samples exceeded the RTE safety threshold (1 × 10⁵ CFU/g). Awara had significantly

higher mean counts (~1.1 × 10⁷ CFU/g) than waina (~6.5 × 10⁶ CFU/g; W = 321, p = 0.0007). S.

aureus (31%), K. pneumoniae (27.5%), P. aeruginosa (23%), and E. coli (18%) were recovered, with

no significant between-food difference in species distribution (χ² = 1.03, p = 0.794). Amoxicillin and

gentamicin resistance exceeded 75% across isolates; ESBL producers were detected in 30–40% of E.

coli and 40–50% of K. pneumoniae. Evening samples consistently showed higher microbial loads.

Conclusion: Both foods harbor MDR bacteria, including ESBL-producing Enterobacteriaceae, far

exceeding safe RTE limits. Vendor hygiene training, safe water access, and integration of street food

surveillance into Nigeria's national AMR action plan are urgently needed.