1. FG35 Division of Gastrointestinal Infections, Zoonoses and Tropical Infections, Robert Koch Institute, Berlin, Germany
2. FG11 Division of Enteropathogenic Bacteria and Legionella, Consultant Laboratory for Listeria, Robert Koch Institute, Wernigerode, Germany
3. German Federal Institute for Risk Assessment, National Reference Laboratory for Listeria Monocytogenes, Berlin, Germany
4. Austrian Agency for Health and Food Safety, Graz, Austria