The aim was to characterize reported food- and waterborne outbreaks in Finland, 2010-2020, and to test local investigation teams’ preparedness to investigate outbreaks.

The outbreaks reported to the Finnish registry for food and waterborne outbreaks were characterized by the number of outbreaks and people fallen ill, and the causative agent. Local investigation teams’ measures and their timeliness in a simulated time-constrained case study were scored and analyzed descriptively.

In 537 outbreaks, 12 399 fell ill and 19 (0.15%) died. The causative agent remained unknown in 218 outbreaks. The local investigation teams’ median preparedness score was 15/29 (range 9-23) and the score differed markedly within regions. Differences in the speed of communication and the number of channels used were observed between the teams.

Differences between environmental health units’ scores indicated inconsistency in outbreak investigations between areas in Finland. The variability in preparedness scores was high in both the highest and lowest outbreak incidence regions. Because outbreaks occur rarely in most EHU areas, preparedness exercises are necessary to maintain investigation skills. Measures to enhance sampling would be needed because the causative agent was unknown in over 1/3 of the outbreaks. Many local investigation teams lack experience in public communication and training on communicating about outbreaks is needed.