Outbreak of Salmonella Agona linked to cross-contamination via doner kebab and electric knives in Hesse and Baden-Wuerttemberg, Germany, January 2022 - December 2024.

OBJECTIVES

Following an increase in Salmonella enterica spp. enterica (S.) serovar Agona notifications in Hesse and Baden-Wuerttemberg, Germany, 2022-2024, we investigated to identify the outbreak vehicle and source to implement control measures.

METHODS

Outbreak cases included laboratory-confirmed S. Agona cases defined as (1) probable (no isolate) or (2) confirmed cases (whole genome sequencing assigned outbreak strain, complex type 20182), residing in Hesse and Baden-Wuerttemberg. We analysed epidemiologic data, including food consumption histories, and compared isolates from clinical, food, and environmental samples.

RESULTS

Sixty S. Agona outbreak cases were identified (Hesse: 25 confirmed, 16 probable; Baden-Wuerttemberg: 15 confirmed, 4 probable), with 83% (40/48) of sequenced isolates closely linked genetically. The median age of cases was 21 years (range: 0-76 years) and 63% (38/60) were male. Cases were more likely to have consumed doner kebab compared to a population-based food survey (OR 6.7, CI 2.66-16.9). In three identified doner restaurants, the outbreak strain was detected in doner meat and on electric knives.

CONCLUSION

Inadequate cleaning of knives due to improper disassembly may have contributed to sustained transmission over the three-year outbreak period. Improved hygiene measures, targeted sampling, and enhanced surveillance are essential to prevent similar foodborne outbreaks.