Isolates may be rapidly confirmed as L. monocytogenes (or not) by using specific test kits. Subtyping of L. monocytogenes isolates is optional except for FDA isolates, which have to be typed serologically, and by pulsed-field gel electrophoresis (PFGE) and by ribotyping. Non-obligatory pathogenicity testing of L. monocytogenes isolates is described.