Viable Counts: Plate Count Quiz

You will be given a virtual sample containing an unknown concentration of bacteria. To determine the viable counts (CFU per ml of sample), you need to dilute the sample and plate on agar.

In this simulation, you will select the volumes of sample and diluent, the number of dilutions you wish to use, and the volume of inoculum you wish to plate. When you then click on "Incubate", colonies will appear on the plate.

If you do not obtain countable plates, you can repeat the dilution process. (You can even ask for a hint if you need one.) Use the number of colonies on the plate to calculate the CFU per ml of sample. Once you have recorded your answer you can check it against the "actual" concentration of bacteria in the sample.

Select the source material to be plated:
Unknown     Transfer
100 ml
Beaker dilution results arrow  
      Remove:  ml
Add to:  ml diluent


Enter an Unknown volume and a Diluent volume to dilute and select "Dilute" or check up to three dilutions to plate and select "Inoculate".



On to Pipetting