3.3.2. *L. monocytogenes* and *S. aureus*

Figure 5A,B present the findings for control samples of *Listeria* and *Staphylococcus* polymicrobial biofilms. The three-dimensional structure embedded in the EPS layer can be observed with *Listeria* cells are at the bottom, to which *Staphylococcus* clusters attach. After treatment with EOs, this structure appears only in micro-colonies with a simple shape, the number of attached cells is decreased, and mainly damaged cells are present. Samples treated with marjoram show split cocci, in agreement with the fact that the EO's target is the cell wall. In some cases, cell debris appears on the surface, which can serve as a possible adhesion site for new cells (Figure 5C–F).
