Environmental sampling for Listeria monocytogenes control in food processing facilities reveals three contamination scenarios

From a total of 2242 FPE samples, L. monocytogenes was present in 32% and 8.8% of meat and dairy processing environments, respectively. In the actual study, each FPE was contaminated with L. monocytogenes on at least one sampling occasion. Three contamination scenarios could be observed: (i) sporadic contamination in the interface of raw material reception and hygienic areas, (ii) hotspot contamination in the hygienic processing areas (iii), and widely disseminated contamination in the entirely FPE. These data demonstrate that L. monocytogenes are common colonizers of FPEs in the European processing facilities sampled and that a consistent cross-contamination risk exists. To avoid food contamination, a risk assessment approach should assign risk levels to critical control areas (CCAs) and identify those where cross-contamination should be essentially excluded.