Figure 4

Scanning electron micrographs of pre- and post-PUV-treated E. coli and L. monocytogenes cells in biofilms. The micrographs are representative of cells in biofilms at 48 h post-inoculation. The images represent cells in biofilms receiving no PUV treatment (control), or PUV treatment for 20 s at a sample to light source distance of 4.5 and 8.8 cm (treated). a E. coli cells on plastic (control); b and c E. coli cells on plastic (treated) 8.8 cm (b) and 4.5 cm (c); d E. coli cells on lettuce (control); d and e E. coli cells on lettuce (treated) 8.8 cm (e) and 4.5 cm (f); g L. monocytogenes cells on plastic (control); h and i L. monocytogenes cells on plastic (treated) 8.8 cm (h) and 4.5 cm (i); j L. monocytogenes cells on lettuce (control); k and l L. monocytogenes cells on lettuce (treated) 8.8 cm (k) and 4.5 cm (l).