Surface-dependent persistence and transfer of Listeria monocytogenes in multispecies biofilms on food-contact surfaces.

Listeria monocytogenes persistence in food processing environments is closely associated with biofilm formation on food-contact surfaces and subsequent transfer to fresh produce. However, the role of native environmental microbiota in shaping pathogen behaviour within biofilms remains poorly understood. This study evaluated biofilm formation, transfer dynamics, cell surface hydrophobicity, and biofilm organization of L. monocytogenes in mono- and multispecies biofilms on stainless-steel (SS), silicone rubber (SR), and polycarbonate (PC) surfaces under low-shear conditions. Multispecies biofilms enhanced L. monocytogenes persistence and modulated cross-contamination dynamics in a surface-dependent manner. On SS, multispecies biofilms showed reduced initial transfer but sustained cumulative transfer across sequential contacts compared to monospecies biofilms, indicating greater structural stability. In contrast, PC exhibited high initial transfer followed by rapid transfer plateauing, whereas SR supported limited accumulation after the first contact event. Higher cell surface hydrophobicity in multispecies biofilms, particularly on SS, was associated with increased biofilm cohesion. Together with fluorescence microscopy observations, these results suggest that biofilm organization, rather than total cell numbers alone, plays a key role in determining persistence and transfer behaviour. Overall, both surface properties and microbial community composition influence L. monocytogenes biofilm stability and cross-contamination risk. Incorporating surface-dependent and ecological factors into hygienic design and sanitation strategies may improve contamination control in fresh produce processing environments.