Phenotypic profiling supports that <i>Listeria costaricensis</i> lacks in vitro pathogenicity but exhibits persistence traits

<i>Listeria costaricensis</i> was recently isolated from a food-processing facility. However, its pathogenic potential and persistence capacity remain poorly characterized at the phenotypic level, raising concerns about food safety. Therefore, we assessed its pathogenic potential through phenotypic invasion and adhesion assays in HeLa cells, showing that <i>L. costaricensis</i> cannot invade HeLa cells despite displaying a cell adhesion capacity comparable to that of <i>Listeria monocytogenes</i> and <i>Listeria innocua</i> reference strains. Given the industrial origin of the strain, we further evaluated its susceptibility to commonly used disinfectants by broth microdilution, finding susceptibility to a mixture of quaternary ammonium compounds (MIC < 100 µg/mL), and reduced susceptibility to peracetic acid (MIC > 160 µg/mL) and sodium hypochlorite (MIC > 500 µg/mL). Considering its demonstrated adhesion capacity, we assessed its ability to form biofilms on polystyrene surfaces, reporting a weak biofilm-forming phenotype comparable to other <i>L. monocytogenes</i> strains. Finally, using the VFanalyzer platform we identified on the <i>L. costaricensis</i> genome 28 virulence-associated gene sequences related to regulatory and structural functions, adherence, and an incomplete invasion gene group compared to <i>L</i>. <i>monocytogenes</i> strains. Collectively, these findings phenotypically support the previously proposed non-pathogenic nature of <i>L</i>. <i>costaricensis</i>, while also revealing a level of persistence comparable to other <i>L. monocytogenes</i> isolates.