In addition to their specific conclusions on the risk assessments of Salmonella spp. in eggs and broiler chickens and L monocytogenes in RTE foods (sections 5.8 and section 6.8), the expert consultation concluded that, overall, the draft risk assessments were comprehensive and of a high quality. Appreciation was expressed for the magnitude of work carried out by the expert drafting groups. The work represented a substantial advance in the application of scientific knowledge to improve the objective basis for managing microbiological hazards in the food chain.
The consultation concluded that the work done by the expert drafting groups should be seen as an exercise, aimed at demonstrating:
the applicability and usefulness of the available methodology;
the need for data based on surveys and experimental studies specifically designed to provide information for microbiological risk assessment;
the need for a better knowledge and understanding of the tails of probability distributions used to describe some input variables (tails provide high or low values, which are less frequent, but can exert a major influence on the predictions of risk);
the opportunity for performing sensitivity or importance analysis so as to give indications to risk managers on where risk management options can be implemented with the best use of resources.
Furthermore, the consultation concluded that validation of results was a relevant part of any modelling exercise. However, there are currently no data available that allow validation of the models used in the exposure assessment and therefore validation of the final risk estimate was not possible. To perform these validations, data are needed on prevalence of contamination and numbers of cells at the point of consumption and/or data on listeriosis and salmonellosis attributable to certain food groups. Given the practical difficulties with regard to validation of risk estimates it would be sensible to develop guidelines for judging the quality of risk assessment models.
The consultation also concluded that the FAO/WHO process for undertaking microbiological risk assessment could be improved and identified some of the key areas to be addressed. In order to critically appraise all elements of a model, its documentation and some instruction on its structure and use could be provided to a peer review panel prior to future expert consultations. Training documents, manuals, guidelines, and quality control procedures are needed in this process. In relation to this the consultation concluded that an international peer review was essential for the credibility of the risk assessments.
