The enumeration of colonies on plates prepared with a spiral
plater is achieved by use of a special counting grid (Figure 5).
• Depending on the relative density of colonies, colonies that
appear in one or more specific areas of the superimposed grid
are counted.
• The volume of sample on certain areas of the plate is known
and colonies on those areas are counted by placing the plates
on a special counting grid.
• Areas of the grid can be related to specific volumes of sample
delivered to those areas.
• Solutions containing between 500 and 500,000 bacteria per mL
can be accurately tested for bacterial numbers using the Spiral
Plate Count System.