Background

Mid-February 2022, the United Kingdom reported via EpiPulse a cluster of monophasic Salmonella Typhimurium infections. Epidemiological and traceback investigations revealed a multi-country outbreak linked to chocolate products from a Belgian factory of an international brand. Microbiological investigations indicated two clusters:  HC5_296366 (cluster 1) and HC5_298160 (cluster 2).  We assessed the extent of the outbreak in Belgium and took measures to limit further spread.

Methods

Probable and confirmed cases were identified using ECDC case definitions. Case-interviews focused on exposure to chocolate products of the concerned brand. Raw materials and finished food products collected at the factory were analysed for Salmonella spp. using real-time PCR. Whole genome sequence (WGS) analysis of isolates of probable cases and positive food samples is still ongoing.

Results

We identified 62 probable cases (39 cluster 1, 23 cluster 2), with illness onset from mid-January until April and a peak in cases mid-February 2022. Of these 62 cases, 54 were aged 1-9 years old. Among the 44 interviewed cases, 19 have been hospitalized and 41 reported consumption of products of the factory among whom 35 reported consumption of Kinder Surprise. Seven of 229 food products tested positive for Salmonella; WGS analysis indicated matches with both clusters. In December 2021, Salmonella was found in samples during a self-check in the factory, these isolates matched with the later identified clusters. Eleven types of products were recalled worldwide and food safety authorities shut down the factory 8 April 2022.

Conclusions

Epidemiological and microbiological investigations confirmed the link between Salmonella cases and products from a Belgian chocolate factory. A strong collaboration and information sharing between different stakeholders resulted in comprehensive measures to stop the spread of this international outbreak.