Icelandic officials have revealed that 17 people have been affected by a Salmonella outbreak from January to May 2024.
The outbreak control team (OCT) included representatives from the chief epidemiologist, local health authorities, Reykjavik health authorities, the Icelandic Food and Veterinary Authority (MAST), the Department of Microbiology at Landspitali University Hospital, as well as district and regional epidemiologists.
The monophasic Salmonella Typhimurium outbreak was identified at the end of January 2024. Initially, the disease appeared to be limited to preschoolers in Húsavík, but cases were subsequently discovered in other regions and among older individuals. Over almost five months, 17 patients ranging in age from less than 1 to 78 years were diagnosed with Salmonella of the same type. Eight cases were women and nine men. Seven were children aged 1 to 3 from Húsavík.
Chicken meat is a common food item and all infected persons had consumed it. Food tests and stool samples from kitchen staff at the kindergarten were negative for Salmonella.
Poultry link
Salmonella Typhimurium was identified in samples from domestic chickens slaughtered in April. This prompted a company called Matfugli to issue a product recall. Whole Genome Sequencing (WGS) results later confirmed that Salmonella Typhimurium strains isolated from infected individuals and the chicken were related, as both were sequence type 34.
This led researchers to suspect that chicken meat was the source of infections. They said the investigation into the outbreak highlighted the importance of WGS in tracing the source of foodborne illness.
Salmonella was detected during chicken slaughter, several weeks after the largest infection peak had occurred. Officials said this means it is not clear when or how the meat was contaminated.
Samples taken at the farm of the flock in question turned out to be negative for Salmonella. This farm is owned by Matfugli. Two additional flocks tested positive for Salmonella at slaughter, probably as a result of cross-contamination with the first group.
No related Salmonella Typhimurium strains have been identified in other European countries.
Monophasic Salmonella Typhimurium had previously been found on only one poultry farm in Iceland, owned by a different producer. Official inspections have also been carried out at this farm, which is now used for egg production. Checks showed that the producer’s own monitoring of Salmonella was in order and that no positive results were found in official samples.
E. coli outbreak
The final report of an outbreak of Shiga toxin-producing E. coli (STEC) in Iceland has also been submitted.
In October, the chief epidemiologist received a report of a confirmed STEC infection in a kindergarten child treated in the Landspítali emergency department. Other children from the same kindergarten also sought medical attention due to gastrointestinal complaints. As of October 25, the number of confirmed cases was 32.
The outbreak affected 49 people, including 45 children attending Mánagarður kindergarten in Reykjavík and four people associated with the school. Twelve children were hospitalized in the Landspítali pediatric ward due to hemolytic-uremic syndrome (HUS), five of whom were admitted to intensive care. Two children required dialysis due to kidney failure. All children have been released from the hospital, but some are still being monitored for related complications.
The study found that ground meat used in a meal served at the kindergarten was the source of infections. Lunch was being cooked on site in the kitchen when the infection occurred. Microbiological tests confirmed the presence of E. coli O145:H25 in both the meat and fecal samples of affected individuals. Meal preparation practices in the preschool, including handling, cooking and storage, were found to be inadequate.
It was likely that the ground meat was not completely thawed when cooking began. Then other ingredients were added. The minced meat did not boil during cooking, then it was cooled at room temperature for a maximum of 5 to 6 hours. It was kept refrigerated overnight. The next day the minced meat was heated up and served for lunch with boiled spaghetti. Some of the meat did not reach the cooking temperature needed to kill E. coli and the bacteria could have multiplied if the food was left at room temperature.
Other food samples were negative for E. coli. It is not clear whether children who normally do not eat meat but became ill, accidentally ate minced meat, became infected through cross-contamination or from other children.
The Reykjavík Health Authority inspected practices at the preschool, implemented enhanced food safety protocols and provided staff guidance. The facility was cleaned and disinfected and resumed operations in early November. To minimize risks, the kindergarten decided to temporarily purchase meals.
MAST contacted a company called Kjarnafæði about findings of E. coli in ground beef. The batch was not sold to the public, only to restaurants and canteens, including three kindergartens. The company contacted all buyers on the same day and were told that all ground meat had been cooked and consumed, so no recall was issued. There were no signs of illness in other buyers.
The mixed minced meat consisted of beef from Germany and mutton from Iceland. Beef was tested by Kjarnafæði upon arrival in Iceland and found to be compliant. Sheep meat came from a slaughterhouse in Kjarnafæði and dated from the 2023 slaughter season. No sample was taken before E. coli entered the minced meat.
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