An outbreak of Salmonella has sickened more than 30 people in Denmark.

The Statens Serum Institut (SSI) said 31 people had been infected by the same type of monophasic Salmonella Typhimurium in recent months.

Patients fell sick in April and May. They include 20 men and 11 women.

Cases are between 5 and 79 years old with a median age of 40. They live throughout the country with 11 cases in Hovedstaden, six each in Nordjylland and Syddanmark, five in Midtjylland and three in Sjælland.

SSI, Danish Veterinary and Food Administration (Fødevarestyrelsen), and DTU Food Institute are searching for what has caused the outbreak.

SSI is whole-genome sequencing isolates from patients and interviewing sick people to try and identify a possible source of infection.

Whole-genome sequencing of bacteria isolated from patients revealed they were very closely related and all belonged to sequence type 34.

Different Salmonella outbreak
This is a different sequence type from the Salmonella Typhimurium outbreak in Denmark that was linked to ground (minced) beef from England.

In March, April, and May, the Statens Serum Institut recorded 62 people who were infected with the same type of Salmonella.

Those sick are 37 men and 25 women. Patients range from under the age of 1 to 83 and the median age is 49 years old. At least 18 people were hospitalized but no deaths have been recorded.

Whole genome sequencing of bacteria isolated from patients revealed they belonged to sequence type 19.

From patient interviews, 35 of 37 people reported eating ground beef prior to disease onset. A trace-back link to Hilton Foods was made through investigation of eight patients’ consumer purchase data. Meat was imported from England and further processed at the Danish site of Hilton Foods.

Hilton Foods Danmark recalled a variety of ground (minced) beef in May. Products were sold in Dagli’Brugsen, SuperBrugsen, 365 Discount, Coop, Irma, and Kvickly stores across the country.

“Hilton Foods Danmark A/S has recently identified an issue relating to beef mince packaged in Denmark. Having traced this to an individual site of one of our suppliers, we have suspended all supply of meat from that site. This supplier is undertaking a thorough investigation, and all supply will remain suspended while the investigation remains ongoing,” said a Hilton Foods spokesperson.