Cucumbers possible culprits of EU Salmonella outbreak

An outbreak of Salmonella Agona (S. Agona) affecting 147 people from five European countries over the last four years may be linked to ready-to-eat (RTE) cucumber.

The majority of these cases (122) have occurred since the beginning of 2017, and the other 25 cases were reported between 2014 and 2016. The European Union is investigating the outbreak, which has been particularly bad in the United Kingdom with 129 reported cases, followed by 15 in Finland, and one in Denmark, Germany and Ireland.

Published on 26 July 2018, a rapid outbreak assessment by the European Centre for Disease Prevention and Control (ECDC) and the European Food Safety Authority (EFSA) stated the outbreak was first detected in the UK using whole genome sequencing (WGS). Experts found that all S. Agona isolates from the five countries were genetically close and there was a seasonal pattern of cases with peaks in April 2017 and 2018. This suggests “an intermittent common source outbreak” which was linked to RTE products containing cucumbers and prepared in the UK.

All the cucumbers originated from Spain for a limited period (from November 2017 to April 2018), but there was no connection between supply chains, and no single primary cucumber producer, processor or distributor.

The assessment stated, “The laboratory results for Salmonella in all cucumber samples, taken either at primary production level in Spain or during distribution to/within UK, were negative.”

So while RTE products containing cucumbers were identified as a possible vehicle of infection, further investigations along the food chain are needed. Until the source of contamination is identified, the assessment warned that new outbreak cases may occur in early 2019, similar to previous years.

According to the rapid outbreak assessment, S. Agona is the 10th most commonly reported Salmonella serotype.

Common symptoms of Salmonella infection include diarrhoea, fever and abdominal cramps, which tend to occur 12–36 hours after infection. Most people recover without treatment, but severe infections are more likely in infants, the elderly and immune-compromised persons.

The ECDC and EFSA encourage authorities to report new human cases and share information across the affected EU countries.

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