Fig. (1) Confocal laser scanning micrographs of biofilms of Listeria monocytogenes ATCC 7644 formed on stainless steel surfaces for 48 hours at 37°C, after treatment with peracetic acid (2.0%, v/v) (A), oleuropein (5.0 mg/mL) (B) or peracetic acid + oleuropein (5.0 mg/mL and 2.0%, v/v, respectively) (C). Untreated (control) L. monocytogenes biofilm is shown in (D). Cells were treated with sanitizer for 1 minute, neutralized and then were stained with bacterial viability kit LIVE/DEAD (Molecular Probes, OR). Viable cells were stained fluorescent green (Syto 9) and non-viable cells were stained red fluorescence (propidium of iodide). Magnification: 630X.