Scanning electron microscopy (SEM)
Biofilms of L. monocytogenes were established in polystyrene
samples of 1 cm2 as described above (item 3.7). After 48 h, the
samples werewashed three times with 2 ml of distillatedwater and
added of 2 ml of surfactin 0.1%. Control samples were added of
distilled water. After 2 h contact with the biosurfactant the samples
were rinsing with 6 ml of distilled water and the dehydration
procedure was carried out with increasing concentrations of
ethanol:water as described by Zeraik and Nitschke (2010). The
samples were maintained desiccated until gold sputtering and
visualized by scanning electron microscope (LEO 440 - Zeiss)
operating at 20 kV.