Updated Parameters for Listeria monocytogenes Dose–Response Model Considering Pathogen Virulence and Age and Sex of Consumer

Abstract

Better knowledge regarding the Listeria monocytogenes dose–response (DR) model is needed to refine the assessment of the risk of foodborne listeriosis. In 2018, the European Food Safety Agency (EFSA) derived a lognormal Poisson DR model for 14 different age–sex sub-groups, marginally to strain virulence. In the present study, new sets of parameters are developed by integrating the EFSA model for these sub-groups together with three classes of strain virulence characteristics (“less virulent”, “virulent”, and “more virulent”). Considering classes of virulence leads to estimated relative risks (RRs) of listeriosis following the ingestion of 1000 bacteria of “less virulent” vs. “more virulent” strains ranging from 21.6 to 24.1, depending on the sub-group. These relatively low RRs when compared with RRs linked to comorbidities described in the literature suggest that the influence of comorbidity on the occurrence of invasive listeriosis for a given exposure is much more important than the influence of the virulence of the strains. The updated model parameters allow better prediction of the risk of invasive listeriosis across a population of interest, provided the necessary data on population demographics and the proportional contribution of strain virulence classes in food products of interest are available. An R package is made available to facilitate the use of these dose–response models.

A Critical Review of Risk Assessment Models for Listeria monocytogenes in Produce

“…Therefore, the construction of a QRA model that encompasses an on-farm module is needed, as it can help assess the effects of current on-farm management practices and preventive measures as well the effects of the type of cultivation on the final risk to the consumers associated with fresh and minimally processed produce. Now that doseresponse relationships based on strain genetics have been proposed [42,43], it would be important to look at the genetic diversity of L. monocytogenes in agricultural soils. Clonal complexes (CC) 1, CC2, CC4, and CC6 are infection-associated clones usually causing sporadic or outbreak listeriosis, while CC9 and CC121 are strongly food-associated clones that mostly infect immunocompromised individuals [44].…”

Public health aspects of Vibrio spp. related to the consumption of seafood in the EU

“…On the other side, molecular methods, and in particular WGS and NGS/WGS methods, may provide a significant and variegate contribution to risk assessment (extensively reviewed in EFSA BIOHAZ Panel, 2019 ). Beside their application in outbreak investigation and source attribution, they can contribute to the hazard characterisation by identifying molecular markers associated with specific phenotypes, or by supporting the definition of strain/virulence‐related DR curves (Pouillot et al., 2024 ). Furthermore, the omics methodologies can be particularly helpful to investigate the variability of vibrios in relation with virulence/AMR, behaviour in food, in the environment and in animal reservoirs (Rantsiou et al., 2018 ) and may provide, with metagenomics, a shift from studying microorganisms dynamics as a standalone towards studying them within the dynamics of the microbial communities.…”