Of the five novel species, there were three cluster with the Listeria sensu stricto clade and two cluster with sensu lato. All five novel species are non-haemolytic and negative for phosphatidylinositol-specific phospholipase C activity; the draft genomes showed lack of virulence genes in Listeria pathogenicity island 1 (LIPI-1), and the internalin genes inlA and inlB, indicating that they are non-pathogenic.

Interestingly, one of the novel species, L. immobilis, lacked motility, or the ability to move (Listeria sp. have flagella, and it is seems to play a key role in detection and invasion).

The researchers said: „This research increases the set of Listeria species monitored in food production environments. Expanding the knowledge base to understand the diversity of Listeria will save the commercial food world confusion and errors, as well as prevent contamination, explain false positives and thwart foodborne outbreaks."