Multi-country outbreak of Listeria monocytogenes linked to consumption of salmon products
Ready-to-eat salmon products, such as cold-smoked and marinated salmon, are the likely source of an outbreak of Listeria monocytogenes that has affected Denmark, Germany and France since 2015. EFSA and the European Centre for Disease Prevention and Control (ECDC) used whole genome sequencing to identify the multi-country outbreak.
By 8 October 2018, 12 cases including four deaths had been reported in the affected countries. In August 2017, Denmark reported the first cluster of cases linked to the consumption of ready-to-eat smoked salmon produced in Poland. Control measures were implemented and other EU Member States and competent authorities were informed. In October 2017 France reported the detection of the same strain of Listeria in marinated salmon originating from the same Polish processing company as identified in the Danish outbreak investigation.
The most recent case linked to the outbreak was notified in Germany in May 2018. Due to the lack of whole genome sequencing data from the environmental and food samples taken at the Polish processing plant, it is not possible at present to confirm whether the contamination occurred in the suspected plant. Moreover, until information on the Norwegian primary producers of the salmon used in the contaminated batches has been reported and assessed, the possibility of contamination at primary production level cannot be excluded.
The identification of the same Listeria strain in a salmon product in France and a new human case in Germany suggest that the source of contamination may still be active and that contaminated products have been distributed to other EU countries than Denmark. Pregnant women, the elderly and immunocompromised people are at higher risk of contracting listeriosis.