A multi-country outbreak of Listeria monocytogenesST6 that caused 53 cases and 10 deaths over
the period 2015–2018, was linked in 2018 to frozen vegetables. The processing of such vegetables
included a blanching step before their freezing. The outbreak was detected using very speciﬁc
molecular analytical methods, facilitating the linkage between human and food isolates. Environmental
contamination of a freezing plant was indicated as the source of the persistence of the strain causing
the outbreak from 2015 until 2018.