Make sure you understand the following concepts — go back to the applets if you need to:
- dilution (stated as a fraction or in scientific notation)
- overall dilution (product of individual dilutions)
- choosing the plate to count (30 to 300 CFUs)
- scaling up from the plate to the population size (multiplying by the dilution factor)
- setting up an appropriate dilution scheme to result in a countable plate
Learning Outcomes
Now you have completed this module, you should be able to:
- Define dilution and dilution factor
- Explain why dilutions are necessary for microbial counts
- Prepare dilutions and calculate total dilution of serial dilutions
- Set up an appropriate dilution scheme to result in a countable plate
- Evaluate and interpret the results of plate counts, including selecting the appropriate plate for counting and scaling up from the diluted sample to the original population
If you want a printer-friendly version of this module, you can find it here in a PDF 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.