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A review of risk factors for 11 foodborne diseases

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News of 27/05/2021

A special issue of the journal Microbial Risk Analysis has just been published, addressing risk factors for the main foodborne infectious diseases. Based on the work of ANSES's scientists and experts, it summarises epidemiological knowledge and provides information to guide preventive measures and the monitoring of these diseases, as well as future research. 

ANSES's scientists compiled the results of no fewer than 673 epidemiological studies published before May 2017 (case-control and cohort studies) that had dealt with risk factors for sporadic foodborne infections. This work was undertaken in collaboration with the Polytechnic Institute of Bragança in Portugal. The resulting meta-analyses focused on 11 pathogens that can be transmitted by food and are significant due either to their frequency or to the severity of the symptoms they can cause:

  • five are bacteria such as Salmonella and Listeria monocytogenes;
  • three are viruses (hepatitis A and E viruses and noroviruses);
  • three are parasites, responsible for toxoplasmosis and giardiasis for example. 
  • Lastly, an article describes the common methodology used for these meta-analyses. 

Classifying exposure routes

The factors of exposure to these pathogens are not exclusively dietary: in addition to the consumption of certain foods and food preparation practices, other routes of contamination were identified, such as person-to-person transmission, contact with animals, and the environment. 

The studies identified which risk factors are most significant for each pathogen and for each population category (general public, children, and people at risk, such as immunocompromised individuals and pregnant women). For example, the main risk factor for Salmonella contamination is the consumption of eggs and meat for the general public; however, for children, it is contact between people. 

Certain routes of exposure have not yet been reported in France and need to be confirmed through specific studies. These include the consumption of eggs or foods made with undercooked eggs as a risk factor for campylobacteriosis; moreover, poultry meat was identified as a source of infection with Shiga toxin-producing Escherichia coli. 

A basis for guiding preventive measures    

These meta-analyses served as a basis for ANSES's Opinion and Report on Source attribution for foodborne infectious diseases (Part 2). The goal of this Opinion and Report was to determine the relative significance of the various transmission routes and food categories involved in foodborne infectious diseases, in order to guide measures aimed at reducing their incidence. This work may guide future epidemiological studies in France, to confirm the identified risk factors. It may also serve as a basis for public health recommendations on unsafe practices and foods.