Prevalence and Molecular Typing of Listeria monocytogenes in Ready-to-Eat Meats in Abuja, FCT

Listeria monocytogenes is a foodborne pathogen of particular concern in ready-to-eat meat products due to its ability to grow at refrigeration temperatures and its severe consequences for immunocompromised individuals. This study determined the prevalence and molecular characteristics of Listeria monocytogenes in ready-to-eat meats sold in Abuja, Federal Capital Territory. A total of 200 ready-to-eat meat samples including suya, roasted chicken, and processed deli meats were collected from retail outlets, supermarkets, and informal vendors in five area councils. Listeria species were isolated using the ISO 11290 method, and confirmed L. monocytogenes isolates were characterized by serotyping and whole-genome sequencing. Virulence genes including hlyA, actA, and inlA were identified bioinformatically. Antimicrobial susceptibility was determined by broth microdilution. L. monocytogenes was detected in 14.5% of samples, with higher prevalence in products from informal vendors compared to supermarkets. Serogroup IVb strains with full-length InlA, associated with greater invasion potential, predominated. Multi-drug resistance was identified in 41.4% of isolates. Phylogenomic analysis revealed two clonal clusters shared across vendor types in the same geographic cluster, suggesting common contamination sources. The study concludes that ready-to-eat meat in Abuja carries a meaningful Listeria contamination burden and recommends enhanced cold chain management, vendor hygiene training, and NAFDAC-led routine surveillance programs for Listeria in ready-to-eat meats. Keywords: Listeria monocytogenes, ready-to-eat meat, molecular typing, Abuja, food safety