2.1. Selection of FPE facilities and sampling
Twelve FPEs located in six European countries (Austria, Ireland, Spain, Slovakia, Greece and Romania) were sampled from March 2012 to March 2013. From previous sampling activities, facility inspections and consultations with quality managers, the L. monocytogenes contamination history was known, resulting in a categorization in presumed uncontaminated (UC) or contaminated (C)-FPEs. The selection of FPEs with regard to the initial contamination status (presumed positive/negative) should enable the determination of contamination dynamics in a positive FPE, or whether a negative FPE could remain negative during the 12 months of investigation. The FPEs included four small farmhouse cheesemaking facilities, five industrial dairy and three meat producers (Figs. 1e6).