Outbreak of Listeriosis Likely Associated with Baker’s Yeast Products, Switzerland, 2022–2024

Abstract

We traced back a nationwide outbreak of human listeriosis in Switzerland to a persisting production line contamination of a factory producing baker’s yeast with Listeria monocytogenes serotype 1/2a sequence type 3141. We used whole-genome sequencing to match clinical isolates to isolates from product samples.

Keywords

• listeriosis
• bacteria
• food safety
• Listeria monocytogenes
• ST3141
• baker’s yeast