2. Place the Petrifilm plate on a level surface, with the gridded side down.
Lift the top film (fig. 2).
Figure 2
3. With pipet perpendicular to the Petrifilm plate, place 1 mL of sample
onto the center of the bottom film (fig. 3). If necessary, samples can be
diluted with distilled water, liquid culture medium, or buffers with pH
between 6.6 and 7.2.* If antibiotics are to be added to the medium, add
them to the inoculating liquid at the working concentration.
Figure 3
4
