The Salmonella and Listeria unit carries out reference, surveillance and research activities focusing on these two major bacterial pathogens involved in foodborne human infections. Its work informs the assessment of the associated health risks and ultimately optimises the management of food safety. Several types of analyses (conventional, molecular and genomic typing, as well as detection and enumeration analyses in food) are carried out according to a quality assurance approach; some of them are covered by a laboratory accreditation.

Reference activities

The unit is responsible for carrying out reference activities on Listeria monocytogenes as part of its National (NRL) and European (EURL) Reference Laboratory mandates. It is also associated with the Salmonella NRL (mandate held by the Ploufragan-Plouzané-Niort Laboratory) for Salmonella serotyping and surveillance activities. The unit provides scientific and technical support to the networks of testing laboratories covered by its reference mandates, as well as to the national and European competent authorities. It contributes to improving detection and characterisation tools for Listeria monocytogenes and Salmonella. It also organises inter-laboratory proficiency and method-validation tests (ILPTs and ILVTs)as well as training sessions on the implementation of the official methods falling under its mandates.

Surveillance activities

The unit is involved in coordinating a network of almost 120 laboratories spread out across France. It participates in the design and implementation of tools contributing to the epidemiological surveillance of Salmonella and Listeria monocytogenes from farm to fork. Strain characterisation results, combined with metadata, continuously document cases of contamination identified in animal, environmental and food reservoirs. The databases generated are regularly used in national and European alert situations to help risk managers direct epidemiological investigations. 

Expert appraisal activities 

The unit’s scientists may be asked to participate in the expert groups of ANSES and the European Food Safety Authority (EFSA) or be involved in the work of standardisation bodies (AFNOR, CEN and ISO). Moreover, the unit helps transfer knowledge to agro-industrial technical institutes via multidisciplinary networks – including joint technology units (UMTs) and joint technology networks (RMTs) – supported by the Ministry of Agriculture. 

Research activities

Several areas of research are currently being developed:

• the integration of molecular and genomic approaches for the characterisation of isolates;
• the structure of populations of these pathogenic bacteria;
• the development of more effective detection, enumeration and typing methods;
• the detection of markers for the virulence, resistance and adaptation of these pathogens in their different reservoirs.

Reference, surveillance and research activities are coordinated in complementary ways in order to characterise these hazards throughout the agri-food chain. The unit carries out its work in a cross-cutting manner with the laboratory and Agency’s food safety units, departments and platforms. It establishes national and international partnerships for all its activities.