More than 100 patients have been added to a multi-country Salmonella outbreak that began in 2021.

By mid-March 2024, 300 Salmonella Mbandaka patients have been reported, according to the European Centre for Disease Prevention and Control (ECDC) and European Food Safety Authority (EFSA).

The United Kingdom has the most cases with 173 and Finland has 98. France has 16, Ireland has seven, while a few have also been reported in Estonia, Germany, and the Netherlands.

Twenty-three patients were hospitalized, six in Finland had septicaemia and one person died in the UK. Patients range in age from less than 1 year old to 100 and 165 are females.

Link to chicken products
Investigations by food safety authorities in Estonia, Finland, and the Netherlands, and the sharing of genomic food information with EFSA in 2024, identified the outbreak strain in frozen steam-cooked chicken breast fillet produced in Ukraine.

The shelf life of contaminated frozen chicken meat products expired in November and December 2023. The latest patients were detected in Finland in October 2023 and in the UK in February 2024, indicating the strain was still circulating in the chicken meat production chain recently.

“Assuming that the identified contaminated batches are no longer on the market, and given the expiration dates and control measures implemented, the likelihood of new infections occurring with the outbreak strain from these batches is low,” said ECDC and EFSA.

In November 2022, 196 cases had been recorded since September 2021. Ready-to-eat chicken products or fresh chicken meat were identified as probable vehicles of infection based on interviews with sick people in Finland and the UK. 

Many patients had consumed products at cafés and restaurants but some in the UK also reported eating chicken bought fresh, indicating that various contaminated products may have been distributed through retail and catering.

Five cases in the Czech Republic and four from Israel mentioned in 2022 were excluded from the latest update as sequencing results showed no genetic relatedness to the outbreak strain.

Despite the implementation of control measures, cases continued to occur throughout 2023 in Europe and in early 2024 in the UK, suggesting undetected routes of exposure which require further investigation and pose a risk for new infections, said ECDC and EFSA.

Origin of contaminated meat
In 2022, a link was made to an Estonian company based on patient interviews and purchase data but there was no microbiological evidence. The food safety authority in Estonia reported this company had not used chicken meat from Ukraine since December 2022. A chilled chicken Caesar ciabatta produced by this company, and sampled in Finland in 2022, was reported as Salmonella Mbandaka-positive. Based on traceability information, the Estonian firm cannot be linked to all countries reporting patients.

Steam cooked frozen chicken breast, from the Ukrainian processor and sampled at an Estonian company in 2022, matched the outbreak strain. Another batch of this product, sampled in 2023 at an Estonian wholesaler and a Dutch company, also tested positive for the outbreak strain.

In January and April 2023, the European Commission, on behalf of Ukraine, communicated in RASFF that corrective measures were reported to have been implemented at the Ukrainian plant such as microbiological testing of each batch exported to Europe, increased Salmonella testing of raw materials coming from the slaughterhouse, and revision of food safety and hygiene procedures.

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