Denmark has revealed norovirus caused the most foodborne outbreaks this past year with Salmonella and Campylobacter in joint second.
In 2024, 55 foodborne outbreaks were registered with 1,126 people sick. Representatives from the National Food Institute at the Technical University of Denmark, Danish Veterinary and Food Administration (Fødevarestyrelsen), and Statens Serum Institut (SSI) said this is nine fewer than in 2023. The number of people sick in outbreaks also fell from 1,760 in 2023.
There were 1,266 Salmonella infections in 2024, up from 1,207 in 2023. Salmonella Enteritidis was the top serotype with 274 patients, of which 66 percent were infected abroad.
Ten Salmonella outbreaks were recorded, including three international incidents. While Salmonella accounted for fewer outbreaks than the previous year, the number of cases remained the same. This was largely because of three major outbreaks – one linked to rocket salad and baby spinach, and two to ground (minced) beef. Denmark had five cases in an international Salmonella Mikawasima outbreak with an unknown source.
Wash salad, don’t taste raw beef
Almost 200 illnesses caused by Salmonella Umbilo were recorded across Europe. In Denmark, 22 people were ill. The outbreak was traced to salad and spinach from an Italian company.
“Studies from DTU and the Danish Veterinary and Food Administration show that rinsing lettuce with cold water can remove up to 80 percent of bacteria. Therefore, Fødevarestyrelsen advises consumers to wash fruit and vegetables, especially if they are to be eaten raw,” said Sørine Quaade Møller, head of section of the Danish Veterinary and Food Administration.
Two large Salmonella outbreaks infected 66 and 70 people, respectively. In the first Salmonella Typhimurium outbreak, cases occurred in four countries and 24 people were hospitalized. An investigation showed the source was beef from England. Hilton Foods traced the issue to one of its suppliers. The processor found a matching outbreak strain in beef samples from the production site.
The second monophasic Salmonella Typhimurium outbreak was linked to beef of Danish origin. Twenty people were hospitalized. In both outbreaks, several patients had eaten the meat raw — either by tasting it before cooking or by consuming it as steak tartare.
“Although EU legislation requires ground (minced) meat to be free from Salmonella, contamination can occur at the slaughterhouse, where the meat may be exposed to harmful intestinal bacteria such as Salmonella or E. coli. If consumers wish to eat steak tartare, minced beef specifically produced for tartare should be purchased,” said Quaade Møller.
Largest outbreak caused by Clostridium perfringens
Norovirus was responsible for 16 foodborne outbreaks, an increase from 13 in 2023. Three outbreaks with 57 cases were related to ill kitchen staff or a healthy carrier of the virus among employees in restaurants. One outbreak with 14 cases was caused by imported raw oysters served in restaurants. Another with 15 patients was because of eating contaminated frozen blackberries.
Seven of 10 Campylobacter outbreaks were linked to chicken meat. A total of 5,546 cases were reported in 2024, up from 5,186 in 2023.
Denmark had 1,269 Shiga toxin-producing E. coli (STEC) infections in 2024, down from 1,431 in 2023. The source was not found in two E. coli O132 and E. coli O26 epidemics with four cases each. Yersinia enterocolitica cases went up from 1,199 in 2023 to 1,296.
There were 61 listeriosis infections in 2024 compared to 54 in 2023. Two Listeria outbreaks spanning seven years were traced to Polar Salmon Hjerting Laks, a Danish fish producer. Patients from Germany, Italy, and Sweden were also linked to these outbreaks and the same Listeria types were found in product samples at the company.
After an inspection by the Danish Veterinary and Food Administration in early 2025, the company was reported to the police for not removing ready-to-eat food contaminated with Listeria identified in their own-control checks in 2023 and 2024 from the supply chain or informing authorities.
A regional outbreak of gastroenteritis among school children was associated with drinking raw cow’s milk and consuming silage.
A small outbreak of hepatitis A with five cases was linked to dried dates.
A Bacillus cereus outbreak with 27 patients at a kindergarten was linked to bread with carrots.
A Clostridium perfringens outbreak caused by pork roast served in a canteen sickened 91 and another incident with 95 cases was blamed on mixed food at a catered event.
An unknown pathogen in porridge for infants sickened 48 people.
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