This document provides guidance for communicators on how to communicate the various expressions of uncertainty described in EFSA's document: 'Guidance on uncertainty analysis in scientific assessments'. It also contains specific guidance for assessors on how best to report the various expressions of uncertainty. The document provides a template for identifying expressions of uncertainty in scientific assessments and locating the specific guidance for each expression. The guidance is structured according to EFSA's three broadly defined categories of target audience: 'entry', 'informed' and 'technical' levels. Communicators should use the guidance for entry and informed audiences, while assessors should use the guidance for the technical level. The guidance was formulated using evidence from the scientific literature, grey literature and two EFSA research studies, or based on judgement and reasoning where evidence was incomplete or missing. The limitations of the evidence sources inform the recommendations for further research on uncertainty communication.

https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/j.efsa.2019.5520

Guidance on Communication of Uncertainty in Scientific Assessments

Abstract This report of the European Food Safety Authority and the European Centre for Disease Prevention and Control presents the results of zoonoses monitoring and surveillance activities carried out in 2021 in 27 MSs, the United Kingdom (Northern Ireland) and nine non‐MSs. Key statistics on zoonoses and zoonotic agents in humans, food, animals and feed are provided and interpreted historically. In 2021, the first and second most reported zoonoses in humans were campylobacteriosis and salmonellosis, respectively. Cases of campylobacteriosis and salmonellosis increased in comparison with 2020, but decreased compared with previous years. In 2021, data collection and analysis at the EU level were still impacted by the COVID‐19 pandemic and the control measures adopted in the MSs, including partial or total lockdowns. Sixteen MSs and the United Kingdom (Northern Ireland) achieved all the established targets in poultry populations for reduction in Salmonella prevalence for the relevant serovars. Salmonella samples from carcases of various animal species and samples for Campylobacter quantification from broiler carcases were more frequently positive when performed by the competent authorities than when own‐checks were conducted. Yersiniosis was the third most reported zoonosis in humans, followed by Shiga toxin‐producing Escherichia coli (STEC) and Listeria monocytogenes infections. L. monocytogenes and West Nile virus infections were the most severe zoonotic diseases, with the most hospitalisations and highest case fatality rates. Overall, MSs reported more foodborne outbreaks and cases in 2021 than in 2020. S. Enteritidis remained the most frequently reported causative agent for foodborne outbreaks. Salmonella in ‘eggs and egg products’ and in ‘mixed foods’ were the agent/food pairs of most concern. Outbreaks linked to ‘vegetables and juices and products thereof’ rose considerably compared with previous years. This report also provides updates on brucellosis, Coxiella burnetii (Q fever), echinococcosis, rabies, toxoplasmosis, trichinellosis, tuberculosis due to Mycobacterium bovis or M. caprae, and tularaemia.

The European Union One Health 2021 Zoonoses Report

Crossing the Intestinal Barrier via Listeria Adhesion Protein and Internalin A.

We present the LiSEQ (Listeria SEQuencing) project, funded by the European Food Safety Agency (EFSA) to compare Listeria monocytogenes isolates collected in the European Union from ready-to-eat foods, compartments along the food chain (e.g. food-producing animals, food-processing environments) and humans. In this article, we report the molecular characterization of a selection of this data set employing whole-genome sequencing analysis. We present an overview of the strain diversity observed in different sampled sources, and characterize the isolates based on their virulence and resistance profile. We integrate into our analysis the global L. monocytogenes genome collection described by Moura and colleagues in 2016 to assess the representativeness of the LiSEQ collection in the context of known L. monocytogenes strain diversity.

LiSEQ - whole-genome sequencing of a cross-sectional survey of Listeria monocytogenes in ready-to-eat foods and human clinical cases in Europe.

Listeria monocytogenes is frequently found in foods and processing facilities, where it can persist, creating concerns for the food industry. Its ability to survive under a wide range of environmental conditions enhances the potential for cross-contamination of the final food products, leading to possible outbreaks of listeriosis. In this study, whole-genome sequencing (WGS) was applied as a tool to characterize and track 100 L. monocytogenes isolates collected from three food processing environments. These WGS data from environmental and food isolates were analyzed to (i) assess the genomic diversity of L. monocytogenes, (ii) identify possible source(s) of contamination, cross-contamination routes, and persistence, (iii) detect absence/presence of antimicrobial resistance-encoding genes, (iv) assess virulence genotypes, and (v) explore in vivo pathogenicity of selected L. monocytogenes isolates carrying different virulence genotypes. The predominant L. monocytogenes sublineages (SLs) identified were SL101 (21%), SL9 (17%), SL121 (12%), and SL5 (12%). Benzalkonium chloride (BC) tolerance-encoding genes were found in 62% of these isolates, a value that increased to 73% among putative persistent subgroups. The most prevalent gene was emrC followed by bcrABC, qacH-Tn6188, and qacC. The L. monocytogenes major virulence factor inlA was truncated in 31% of the isolates, and only one environmental isolate (L. monocytogenes CFS086) harbored all major virulence factors, including Listeria pathogenicity island 4 (LIPI-4), which has been shown to confer hypervirulence. A zebrafish embryo infection model showed a low (3%) embryo survival rate for all putatively hypervirulent L. monocytogenes isolates assayed. Higher embryo survival rates were observed following infection with unknown virulence potential (20%) and putatively hypovirulent (53 to 83%) L. monocytogenes isolates showing predicted pathogenic phenotypes inferred from virulence genotypes. IMPORTANCE This study extends current understanding of the genetic diversity among L. monocytogenes from various food products and food processing environments. Application of WGS-based strategies facilitated tracking of this pathogen of importance to human health along the production chain while providing insights into the pathogenic potential for some of the L. monocytogenes isolates recovered. These analyses enabled the grouping of selected isolates into three putative virulence categories according to their genotypes along with informing selection for phenotypic assessment of their pathogenicity using the zebrafish embryo infection model. It has also facilitated the identification of those isolates with genes conferring tolerance to commercially used biocides. Findings from this study highlight the potential for the application of WGS as a proactive tool to support food safety controls as applied to L. monocytogenes.

https://www.zora.uzh.ch/id/eprint/184799/1/mSphere-2019-Hurley-e00252-19.full.pdf

Whole-Genome Sequencing-Based Characterization of 100 Listeria monocytogenes Isolates Collected from Food Processing Environments over a Four-Year Period

Food safety criteria for Listeria monocytogenes in ready-to-eat (RTE) foods have been applied from 2006 onwards (Commission Regulation (EC) 2073/2005). Still, human invasive listeriosis was reported to increase over the period 2009-2013 in the European Union and European Economic Area (EU/EEA). Time series analysis for the 2008-2015 period in the EU/EEA indicated an increasing trend of the monthly notified incidence rate of confirmed human invasive listeriosis of the over 75 age groups and female age group between 25 and 44 years old (probably related to pregnancies). A conceptual model was used to identify factors in the food chain as potential drivers for L. monocytogenes contamination of RTE foods and listeriosis. Factors were related to the host (i. population size of the elderly and/or susceptible people; ii. underlying condition rate), the food (iii. L. monocytogenes prevalence in RTE food at retail; iv. L. monocytogenes concentration in RTE food at retail; v. storage conditions after retail; vi. consumption), the national surveillance systems (vii. improved surveillance), and/or the bacterium (viii. virulence). Factors considered likely to be responsible for the increasing trend in cases are the increased population size of the elderly and susceptible population except for the 25-44 female age group. For the increased incidence rates and cases, the likely factor is the increased proportion of susceptible persons in the age groups over 45 years old for both genders. Quantitative modelling suggests that more than 90% of invasive listeriosis is caused by ingestion of RTE food containing > 2,000 colony forming units (CFU)/g, and that one-third of cases are due to growth in the consumer phase. Awareness should be increased among stakeholders, especially in relation to susceptible risk groups. Innovative methodologies including whole genome sequencing (WGS) for strain identification and monitoring of trends are recommended.

Johanna Takkinen

Papers

Listeria monocytogenes contamination of ready-to-eat foods and the risk for human health in the EU.