Trends and prevalence of <i>Listeria monocytogenes</i> at poultry abattoirs in Taiwan 2014–2024

1. <i>Listeria monocytogenes</i> (<i>L. monocytogenes</i>) 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 <i>L. monocytogenes</i> in poultry carcasses at abattoirs across Taiwan is limited.2. This study investigated <i>L. monocytogenes</i> 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 <i>L. monocytogenes</i> (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 <i>L. monocytogenes</i> 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 <i>L. monocytogenes</i> 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.