Towards harmonization of Campylobacter risk assessment

Abstract:

As part of a collaboration between Danish scientists from DTU, the SECALIM unit aimed to examine the possibility of using the quantitative microbiological risk assessment (QMRA) model associated with the food pathogen Campylobacter spp. already used in Denmark as part of its Campylobacter control plan, on data collected in abattoirs with a view to harmonizing Campylobacter risk assessment on a European scale. The use of French Campylobacter contamination data from 2020-2021 on poultry neck skin samples, collected from thirteen slaughterhouses in western France, necessitated a number of adaptations to the Danish model. A conversion factor had to be applied to transform neck skin contamination data currently collected in Europe into leg skin data used by the model. A relative risk associated with Campylobacter was thus estimated for the year 2021 in relation to the year 2020 chosen as the reference year. The model estimated that this risk had increased by 22% between 2020 and 2021. The estimates and assumptions made to adapt the French data to the Danish model proved to have little impact on the estimated risk.

The study highlights the strengths and limitations of adapting French data into the Danish model, and suggests improving the representativeness of the samples tested to reduce the uncertainty of risk estimates. Further research is needed to better understand the relationship between contamination concentrations on neck skin samples and those on meat consumed.

Background and issues :
Since the introduction of a process hygiene criterion relating to Campylobacter not to be exceeded on poultry carcasses, Campylobacter contamination data are collected within each French slaughterhouse on neck skins in order to assess possible non-compliances. These surveillance data are currently being used to implement risk mitigation actions at individual slaughterhouses where non-compliance has occurred. A quantitative risk assessment model fed by data from all national slaughterhouses would enable actions to be taken on a national or even European scale. The challenge therefore lies in developing a QMRA model that could harmonize Campylobacter risk assessment across Europe.

Results:
The QMRA model used by Denmark in its Campylobacter control plan was adapted to allow the use of neck skin contamination data aggregated over several samples and possibly censored. A relative risk of campylobacteriosis was calculated for the year 2021 compared with the reference year 2020. According to the model, the risk of campylobacteriosis had increased by 22% between 2021 and 2020, with a limited impact of the estimated value of the conversion factor, the random sampling method used and the censored data, on the risk estimates. The limitations and strengths of using pooled data collected within slaughterhouses are analyzed.

Outlook:
The study provides a proof of concept for the use of pooled Campylobacter contamination data in abattoirs, and points to ways of improving data collection, which would enable these data to be better integrated into a QMRA model, compatible with harmonization at European level.

Valorization :
Lauriau, F., M. Nauta, N. Haddad, S. Strubbia, J.-M. Cappelier, M. Sandberg, S. Guillou and A. Foddai 2024. Harmonizing Campylobacter risk assessments across European countries – can the pooled process hygiene criteria data be used in the Danish risk assessment model? Microbial Risk Analysis 27-28: 100325. https://doi.org/10.1016/j.mran.2024.100325.