A framework for the recursive risk-ranking of foodborne zoonotic threats along food supply chains

The threat of foodborne disease outbreaks poses a significant challenge to food safety and public health. Novel pathogens are emerging, and old diseases are re-emerging in complex and long food supply chains that increase the number of pathways for food contamination. Hence, there is growing recognition of the importance of risk prioritization for food safety systems and for supporting risk-based decision making. In this paper, we propose a framework for the recursive risk-ranking of foodborne zoonotic threats along food supply chains, which considers both the multidimensional nature of the impact assessment and the probabilistic estimates of the prevalence of zoonotic pathogens in food supply chains. Although the entire food chain from stable to table must be assessed and controlled to eradicate zoonotic diseases in animal reservoirs and prevent human infections (following the One Health concept), we focus on foodstuffs as sources of pathogens because they directly lead to exposure through consumption. The framework allows iterative application of the evaluation model to prioritize threats and update these priorities as new evidence emerges, while also enabling refinement of the model as the decision context evolves. We assessed the framework at the German Federal Institute for Risk Assessment with encouraging results. We discuss our results and the potential benefits of such recursive assessments for managing supply-chain food risks and enhancing national and global food safety.