IN Brief:
- UKHSA has identified 207 confirmed Salmonella Enteritidis cases in one genetically defined outbreak, including one associated death.
- Egg consumption remains the strongest epidemiological signal, while affected businesses received eggs from several sources including importers.
- Investigators are tracing food chains and possible cross-contamination, with no identified link to UK-produced eggs or poultry at present.
The UK Health Security Agency is investigating a nationwide Salmonella Enteritidis outbreak involving 207 confirmed cases, with egg consumption providing the strongest epidemiological signal so far and food-chain investigations examining suppliers including egg importers.
The outbreak was identified on 26 May 2026 after whole genome sequencing showed an increase in infections caused by a single strain. By 13 August, UKHSA had identified 207 confirmed cases with specimen dates between 11 August 2025 and 1 August 2026, with 206 of the cases reported during 2026.
England accounts for 199 cases, while Scotland has recorded six and Wales and Northern Ireland one each. London has the highest regional total in England with 47 cases, followed by Yorkshire and the Humber with 38.
The cases range from infants to people aged 90, with a median age of 30. Among cases for whom the relevant information is available, 38% were admitted to hospital because of salmonellosis symptoms, two developed bloodstream infections, and one death has been associated with the outbreak.
The genetic evidence places all 207 cases within the same five-single-nucleotide-polymorphism single-linkage cluster. UKHSA says this pattern indicates a common source of contamination, but the precise source and origin remain under investigation.
Investigators have interviewed 114 cases using regional or outbreak questionnaires. Of those, 95 reported eating food prepared outside the home during the week before their symptoms began, placing food-service and catering supply chains prominently within the investigation.
Case interviews identified five food businesses attended by two or more independent cases, linking 24 infections in total. Eleven of those people reported eating dishes made with eggs, and UKHSA says egg consumption remains the strongest signal detected in the investigation to date.
The distinction between a signal and a confirmed source is important. Food-chain investigations have established that the businesses received eggs from multiple suppliers, including importers, so investigators have not attributed the outbreak to one producer, country, importer, or batch.
Local investigations have also found possible cross-contamination events at two of the settings. That widens the work beyond product provenance because contaminated food can expose additional ingredients, utensils, preparation areas, or finished dishes after it has entered a kitchen or catering operation.
At present, UKHSA reports no identified link to UK-produced eggs or poultry. The Food Standards Agency is working with local-authority environmental health teams, which have provided food-safety management advice to businesses where issues have been identified.
The outbreak is unlikely to be primarily travel-related. Only six of the 207 cases reported international travel, leaving domestic food-chain exposure as the main focus for epidemiological and traceability work.
The genetic evidence also connects the current cluster to an earlier Salmonella Enteritidis outbreak investigated during 2025, which was linked to imported eggs. UKHSA, the Animal and Plant Health Agency, the Food Standards Agency, and the devolved administrations are combining information from the two investigations to examine whether wider risks associated with imported eggs can be identified.
The work comes against a period of sustained Salmonella activity in England. UKHSA recorded 10,406 non-typhoidal Salmonella cases during 2025, the highest annual total in a decade, although that wider surveillance figure does not establish the cause of the current outbreak.
For manufacturers, distributors, caterers, and food-service operators handling eggs, the investigation places traceability under close scrutiny. When several suppliers feed multiple businesses, investigators need reliable information covering provenance, batch or lot identification, delivery dates, onward distribution, storage, and use before the chain can be reconstructed accurately.
The possible cross-contamination findings demonstrate why supplier records alone cannot resolve every outbreak. A contaminated ingredient can be the starting point, but preparation practices, segregation, cleaning, storage, and handling determine whether exposure remains confined to one food or spreads through a wider operation.
Eggs can also enter food-service production through more than one format, including shell eggs and processed egg products, while different menu items can share preparation surfaces and equipment. Establishing which ingredient was present is therefore only part of the work required to determine where contamination entered and how people were exposed.
Whole genome sequencing has given investigators a tightly defined group of cases, enabling infections reported at different times and locations to be examined as part of one outbreak. The remaining task is largely a food-chain problem: connecting that genetic cluster to an origin, distribution route, or handling event that can explain the pattern.
Until that evidence is established, imported eggs remain an investigative focus rather than a confirmed single source. The next significant development will be whether tracing work identifies a common supplier or origin, or whether contamination and cross-contamination across several businesses prove to have produced a more complicated chain of exposure.