Multi-country outbreak of Salmonella Typhimurium linked to chocolate products – Europe and the United States of America

On 27 March 2022, the United Kingdom notified WHO of a cluster of cases with monophasic Salmonella Typhimurium sequence type 34 infection.  Investigations linked the outbreak to chocolate produced in Belgium, which have been distributed to at least 113 countries.  A global alert was released by INFOSAN on 10 April, initiating a global product recall.  To date, a total of 151 genetically related cases suspected to be linked to the consumption of the implicated chocolate products have been reported from 11 countries.  The risk of spread in the WHO European region and globally is assessed as moderate until information is available on the full recall of the products.

Outbreak overview

On 27 March 2022, WHO was informed by the IHR National Focal Point of the United Kingdom of Great Britain and Northern Ireland (the United Kingdom) of a widely distributed cluster of Salmonella enterica serovar Typhimurium(S. Typhimurium) with an unidentified source.  Molecular typing confirmed isolation of the bacteria S.

Typhimurium sequence typing (ST) 34 and epidemiological evidence has subsequently linked the outbreak to chocolate products from Belgium, which, as of 25 April 2022, have been found to be distributed to at least 113 countries and territories (list) across all WHO Regions.

Monophasic S. Typhimurium matching the human outbreak cases were identified in buttermilk tanks at the Ferrero Corporate plant in Arlon, Belgium in December 2021 and January 2022.  After implementing hygiene measures and negative Salmonella testing, the implicated products (all Kinder products manufactured at the implicated facility (Arlon) including Kinder Surprise, Kinder Mini Eggs, Kinder Surprise Maxi 100g and Kinder Schoko-Bons) were distributed across Europe and globally.

According to the analyses of the United Kingdom Health Security Agency (UKHSA), the outbreak strain is resistant to six types of antibiotics: penicillins, aminoglycosides (streptomycin, spectinomycin, kanamycin, and gentamycin), phenicols, sulfonamides, trimethoprim, tetracyclines.

As of 25 April 2022, a total of 151 genetically related cases of S. Typhimurium suspected to be linked to the consumption of the implicated chocolate products have been reported from 11 countries (Figure 1): Belgium (26 cases), France (25 cases), Germany (10 cases), Ireland (15 cases), Luxembourg (1 case), the Netherlands (2 cases), Norway (1 case), Spain (1 case), Sweden (4 cases), the United Kingdom (65 cases) and the United States of America (1 case).

Symptom onset dates of cases ranged from 21 December 2021 to 28 March 2022.  Children under 10 years of age (n=134; 89%) were disproportionately affected and females represented 66% (n=99) of reported cases.  Information on reported symptoms and severity were available for 21 cases, and of these, 12 (57%) reported bloody diarrhea and nine (43%) were hospitalized.  As of 25 April 2022, no fatalities associated with the outbreak has been reported.

Epidemiology of Salmonellosis

Salmonellosis is a disease caused by nontyphoidal Salmonella bacteria.  While approximately 2,500 serotypes have been identified, the majority of human infections are caused by two serotypes of Salmonella: Typhimurium and Enteritidis.

Salmonellosis is characterized by acute onset of fever, abdominal pain, nausea, vomiting, and diarrhea that can be bloody as reported in most of the cases in the current outbreak.  The onset of symptoms typically occurs 6–72 hours after ingestion of food or water contaminated with Salmonella, and illness lasts 2–7 days.  Symptoms of salmonellosis are relatively mild and patients will make a recovery without specific treatment in most cases.  However, in some cases, particularly in children and elderly patients, the associated dehydration can become severe and life-threatening.

Salmonella bacteria are widely distributed in domestic and wild animals, such as poultry, pigs, and cattle; and in pets, including cats, dogs, birds, and reptiles such as turtles.  Salmonella can pass through the entire food chain from animal feed, primary production, and all the way to households or food-service establishments and institutions.  Salmonellosis in humans is generally contracted through the consumption of contaminated food of animal origin (mainly eggs, meat, poultry, and milk).  Person-to-person transmission can also occur through the faecal-oral route.

Prevention of salmonellosis: Prevention requires control measures at all stages of the food chain, from agricultural production, to processing, manufacturing and preparation of foods in both commercial establishments and at home.