Trends and prevalence of Listeria monocytogenes at poultry abattoirs in Taiwan 2014–2024

Abstract

1. Listeria monocytogenes (L. monocytogenes) is a Gram-positive bacterium and a significant foodborne pathogen that causes listeriosis and occurs in animal products and other foods. Information on the prevalence of L. monocytogenes in poultry carcasses at abattoirs across Taiwan is limited. 2. This study investigated L. monocytogenes contamination in poultry carcasses at abattoirs across Taiwan from 2014 to 2024, covering chickens (2014–2024), ducks (2019–2024) and geese (2020–2024) slaughter lines. 3. In 2014, 20% of post-chill chickens tested positive for L. monocytogenes (95% CI: 15.1–25.6). Following government intervention and mandatory monitoring across 2014–2024, the prevalence declined steadily and was 0% in 2022–2024. Among all chicken isolates, 73 samples (56.6%) were identified as serogroup 1/2a, 3a; 26 (20.2%) as serogroup 1/2b, 3b; 2 (1.6%) as serogroup 1/2c, 3c; 2 (1.6%) as serogroup 4b, 4d, 4e; and 26 isolates were non-typable. Among all poultry species examined, ducks showed L. monocytogenes in 0.7% (95% CI: 0.0–3.9) of samples in 2019 and 0.5% (95% CI: 0.0–2.7) in 2020; both isolates belonged to serogroup 1/2a, 3a. 4. Among all poultry species examined, geese had detection rates of 0.9% (95% CI: 0.0–4.7) in 2020 and 0.8% (95% CI: 0.0–4.6) in 2021. One sample was identified as serogroup 1/2a, 3a, while the other was classified as serogroup 4b, 4d, or 4e. 5. Since L. monocytogenes is commonly linked to animal-derived and ready-to-eat foods, nationwide surveillance at abattoirs, together with official controls and industry improvements, is crucial for ensuring food safety.