A study conducted by researchers from the UK Food Standards Agency (FSA), Newcastle University, and the University of Southampton suggests that international comparisons of foodborne illness rates are “problematic.” This is likely because, as foodborne illness estimation models are specific to each country, some disparities in estimated rates between countries can be attributed to differences in methodology rather than real differences in risk.

The COVID-19 pandemic shone a light on difficulties in comparing illness rates across counties, and, in light of Britain’s exit from the EU, being able to understand and compare foodborne illness rates internationally has become increasingly important to risk assessments related to food trade. Therefore, the study aimed to determine whether differences in foodborne illness rates internationally are real or due to differences in modelling approaches.

The researchers compared foodborne illness estimates for the UK with those from Australia, Canada, and the U.S. Next, a sensitivity analysis was conducted by recreating the mathematical models used in each country, to understand the impact of key differences in approach and to enable more one-to-one comparisons.

Results showed estimates of overall foodborne illness rates in the UK to be lower than the other countries. However, when UK estimates were adjusted to a more similar approach to the other countries, differences were smaller and often had overlapping credible intervals. When comparing rates by specific pathogens, there were fewer differences between countries. The few large differences found, such as virus rates in Canada, could partly be traced to methodological differences.

Overall, the study highlights the uncertainty in estimates of foodborne illness and how differences in methodology can impact results making comparisons between countries problematic.