A multi-country outbreak of Salmonella Mbandaka linked to pre-cooked, frozen chicken meat in ready-to-eat products, Finland, 2022 to 2023

In May 2022, the Finnish Institute for Health and Welfare observed an increase in <i>Salmonella</i> Mbandaka cases. Whole genome sequencing (WGS) linked the outbreak strain to a previously reported strain in the United Kingdom. From April 2022 to January 2023, 97 cases were reported across 18 of Finland's 21 hospital districts, with a median age of 27 years (range <1-74 years) and 61% female cases. Based on trawling interviews and national food consumption data, cases were more likely to have eaten at a restaurant or takeaway (odds ratio (OR) = 115; 95% confidence interval (CI): 52-256; p < 0.001) or consumed poultry products (OR = 28; 95% CI: 7-115; p < 0.001). A case-case study linked cases with consumption of ready-to-eat products containing chicken from a specific company (OR = 28; 95% CI: 1.9-1,361; p = 0.004). Traceback investigations identified a pre-cooked, frozen chicken meat product from a country outside the European Union as the likely source. <i>Salmonella</i> Mbandaka was isolated from cases and linked by WGS to this chicken meat product. Our findings highlight the potential health risk of pre-cooked chicken meat containing <i>Salmonella</i> and the value of case-case studies and product images to assist recall during food-borne outbreak investigations.