Listeria monocytogenes (Lm) is a ubiquitous bacterium responsible for a rare but serious infection: listeriosis. Transmitted through the consumption of contaminated food, listeriosis is fatal in 20% to 30% of cases. It mainly affects people with a weakened immune system. Therefore, the surveillance of strains isolated from the food chain and the environment is essential. An effective food chain surveillance

system requires the centralisation of high-quality data and the production of useful and accessible information. ANSES, under its mandates as National Reference Laboratory (NRL) and European Union Reference Laboratory (EURL) for Lm, provides scientific and technical support prior to this data collection. In particular, it harmonises typing methods for strains isolated from the food chain, and organises training and inter-laboratory proficiency tests for laboratories in the French and European networks. In France, as part of the ARMADA Joint Technological Unit (UMT), ANSES and the French Pork and Pig Institute (IFIP) have been working for four years on the development of a national database for the  centralisation and sharing of epidemiological and genetic data on the strains held by the two  organisations. Over time, it will be shared with four other French technical institutes and the ANSES laboratories involved in Lm surveillance. This database is interconnected with the European database

system developed by the EURL and the European Food Safety Authority, which makes it possible to report data collected nationwide at European level. The database of the ARMADA UMT currently contains 1,200 strains typed by PFGE, sharing 256 combined ApaI/AscI profiles. This tool is enhancing the surveillance of strains circulating in the various food sectors in France.