EU Multi-Country Salmonella Outbreak Reveals Vulnerabilities in Agri-Food System
A post-incident review of a multi-country European foodborne illness outbreak has exposed gaps in biosecurity, surveillance, and data transparency across the agri-food system. The review was authored by researchers at the University of University of Molise and the University of Turin in Italy, as well as the Italian General Directorate for Health Protection and Coordination of the Regional Health System, and was published in the International Journal of Environmental Research and Public Health.
In 2024, a rare serotype of Salmonella enterica—specifically, S. Umbilo—caused a multinational foodborne illness outbreak spanning the EU/European Economic Area (EEA), resulting in more than 200 confirmed human cases and one fatality. Epidemiological evidence linked the outbreak to the consumption of organic rocket salad and baby spinach originating from the Province of Salerno, Italy—a region known for its intensive buffalo farming and high-value vegetable production.
During the outbreak investigation, initial inspections of processing facilities and irrigation systems revealed no major hygiene violations. Eventually, continued investigations uncovered a mismanaged, unauthorized manure storage tank of unknown ownership near the greenhouses where the implicated greens were grown. Geospatial analysis identified three buffalo farms within a one-kilometer (km) radius of the manure tank, and subsequently, veterinarians dispatched to these farms found buffalo calves presenting enteric symptoms at all three establishments. Fecal samples confirmed the calves were infected with S. Umbilo, S. Livingstone, and S. Senftenberg. Notably, two of the isolated serotypes were also the subject of EU Rapid Alert System for Food and Feed (RASFF) alerts for produce.
Core genome Multi-Locus Sequence Typing (cgMLST) revealed a close genetic match among S. Umbilo isolates from buffaloes, contaminated vegetables, and human cases, confirming a zoonotic transmission pathway. Although samples from the manure tank tested negative for Salmonella, delayed sampling and environmental factors likely influenced the results.
The outbreak exposed critical food safety vulnerabilities in the agri-food system, particularly in regions where raw-consumed vegetables are cultivated alongside high-density livestock operations. Despite existing controls for bovine brucellosis and tuberculosis, no national program currently addresses salmonellosis in ruminants. The detection of zoonotic serotypes in buffalo farms underscores the need for rigorous surveillance and biosecurity measures in high-risk sectors.
In response, regional authorities implemented a six-month Health Management and Control Plan (PSG) for dairy farms, integrating biosecurity protocols and environmental monitoring. These measures reflect a growing recognition of the One Health approach, which emphasizes the interconnectedness of human, animal, and environmental health.
A major challenge highlighted by the outbreak was the restricted access to critical epidemiological and microbiological data. Aggregated reporting and limited transparency hindered efforts to reconstruct outbreak dynamics and identify transmission pathways. The absence of open access to genomic, clinical, and environmental datasets significantly delayed coordinated response efforts.
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The study advocates for the creation of interoperable, open-access databanks to support cross-sectoral research and rapid public health interventions. Enhanced data-sharing would enable timely outbreak detection, facilitate interdisciplinary collaboration, and strengthen the implementation of One Health strategies.
To prevent future outbreaks, stakeholders across the livestock, dairy, and produce sectors must engage in proactive risk management, say the study’s authors. This includes revising Good Manufacturing Practices (GMP), updating Hazards Analysis and Critical Control Points (HACCP) plans, and adopting innovative technologies such as drone surveillance for environmental monitoring.
