Table of Contents

• 1: Recap the story
• 2: Count 'em all?
• 3: Direct count
• 4: Light scatter (using spec)
• 5: The dilemma of the dead cell
• 6: Viable plate count
• 7: Comparison of methods
• 8: Review

Review

In this module you have learnt some of the techniques that can be used for counting bacterial cells.

• The direct count, which uses a microscope to detect and count bacterial cells that have been loaded on a slide or a counting chambe
• The spectrophotometric method, which uses a spectrophotometer. This method doesn't exactly count the bacteria, but it does measure how much light is absorbed by bacterial cells in suspension, and based on that, a standard curve can be used to decide how many bacteria there are.
• The viable plate count, which, unlike the other two techniques, allows you to determine how many bacterial cells are alive in a bacterial population.

The next module, "Viable Plate Count, or How to Count to a Million," will show you all the steps and calculations involved in performing a viable plate count by using a serial dilution technique.

If you want a printer-friendly version of this module, you can find it in this Microsoft Word document. This printer-friendly version should be used only to review, as it does not contain any of the interactive material, and only a skeletal version of problems solved in the module.