Risk Characterization for a Multi-Pathway Quantitative Risk Assessment Model: A Case Study on Extended-Spectrum Beta-Lactamas Producing E. coli Spread From Broiler Production.

This article revisits the risk characterization phase in Quantitative Microbial Risk Assessment (QMRA) and proposes a methodological framework to translate probabilistic risk estimates into easily interpretable public health metrics, thereby facilitating risk communication. This framework adopts a top-down perspective, aiming to estimate the public health burden on a particular population associated with the exposure to a specific microbial hazard originating from a predefined production process. Such an approach is useful for risk managers to compare the relative health impacts of a food production system under different scenarios. It also allows a mathematically rigorous use of QMRA model outputs, even when model validation is constrained by unavoidable data and knowledge gaps. The proposed approach is illustrated using a multi-pathway QMRA model from the literature, assessing the transmission of Extended-Spectrum Beta-Lactamase (ESBL)-producing Escherichia coli (E. coli) to humans through broiler production. Under a baseline scenario defined by a parameterized production system and for a given population, the proposed approach classifies different exposure pathways according to their per-individual risk of colonization, while accounting for the proportion of the general population exposed to each pathway.