Pour plate method

Definition

The pour plate method is a microbiological technique used to isolate and quantify bacteria by diluting a sample and mixing it with molten agar before pouring it into a Petri dish. This allows colonies to grow within the medium, making it easier to count and identify individual colonies.

5 Must Know Facts For Your Next Test

1. The pour plate method helps in determining the number of viable microorganisms in a sample.
2. It involves serial dilution of the sample to achieve isolated colonies in the agar medium.
3. Colonies can grow both on the surface and within the depth of the agar, providing a 3D growth perspective.
4. The method is useful for detecting both aerobic and anaerobic organisms depending on their location within the agar.
5. This technique helps in preventing overcrowding of colonies, which aids in accurate counting.

Review Questions

• What is the primary purpose of using the pour plate method?
• How does serial dilution play a role in the pour plate method?
• What advantage does growing colonies within agar provide compared to surface plating?

Related terms

Serial Dilution: A stepwise dilution of a substance in solution to reduce concentration for further analysis or testing.

Colony Forming Unit (CFU): A term used to estimate the number of viable bacteria or fungal cells in a sample.

Spread Plate Method: A microbiological technique where diluted microbial samples are spread evenly over an agar surface for colony isolation.