Joint FAO/WHO Expert Meetings on Microbiological Risk Assessment (JEMRA)
The Joint FAO/WHO Expert Meetings on Microbiological Risk Assessment (JEMRA) is an international scientific expert group administered jointly by the Food and Agriculture Organization of the United Nations (FAO) and World Health Organization (WHO).
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Web-based tool for listeriosis risk assessment in foods

Risk assessment models for listeriosis on Ready-to-eat (RTE) diced cantaloupe, frozen vegetables, and RTE cold-smoked fish were developed to support the Joint FAO/WHO meeting on microbiological assessment on Listeria monocytogenes developed (MRA48). In this process, WHO developed a web-based risk assessment tool, with a user-friendly interface using Shiny application platform.

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Overview of the Tool

The “WHO Risk Estimation Tool for Listeria monocytogenes in Foods” allows users to estimate overall risk across different scenarios by selecting relevant parameters and evaluating potential interventions throughout the production and distribution chain.

Dose–Response Modelling

Users can choose the dose-response model for consumer risk estimation, including an enhanced model that integrates the virulence class of L. monocytogenes and demographic variables such as age and sex, thereby improving the precision of risk assessments across population groups and strain types.

Evaluation of Testing Strategies

The tool allows users to assess the impact of different testing strategies and sample sizes, supporting informed decision-making under varied production and surveillance conditions.

 

 

 

WHO Risk Estimation Tool for Listeria monocytogenes in Foods screenshot

 

Supplementary material

R packages were developed with functions to apply to the quantitative risk assessment and dose-response models. All the data and code used to make those inferences are available on open-source repositories:

 

Side event videos

To explain the outcomes of the work and introduce the developed tool, on 14 December 2025, at the time of the Fifty-fifth session of the Codex Committee on Food Hygiene (CCFH55), WHO hosted a side event entitled Risk assessment of Listeria monocytogenes: practical tool and insights from the JEMRA model in collaboration with FAO and the experts who were involved in the work.

The recordings (English, French and Spanish) are available on the Nutrition and Food Systems Community of Practice platform (the registration is needed).