How to Properly Sterilize and Prepare petri dishes for Experiments

How to Properly Sterilize and Prepare petri dishes for Experiments


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  • Source: Microbioz India

  • Date: 23 Oct,2023

In microbiology, cell culture, and other laboratory operations, sterilizing and setting up petri dish for research is crucial to ensuring a contaminant-free environment for growing microorganisms or carrying out studies.

Here’s a step-by-step guide on how to properly sterilize and prepare petri dishes:

Materials Needed:

  1. Petri dish
  2. Autoclave or pressure cooker
  3. Distilled water
  4. Agar or growth medium (if applicable)
  5. Sterile cotton swabs or pipettes (if applicable)


Gather and Assemble Equipment:

  1. Make sure your workspace, supplies, and equipment are sanitized and clear of pollutants.
  2. Put on the proper personal protection gear, such as gloves and lab coats.

Preparation of Agar (if applicable):

  1. If you’re using Petri plates to grow microorganisms on agar, get the agar medium ready in accordance with the needs of your particular experiment. Follow the agar preparation guidelines, sterilizing it if necessary.


  1. Write the date, your name, the name of the experiment, and any other pertinent information on the label of each Petri dish. Use labeling tape or a sterile marker.


  1. Use an autoclave or pressure cooker to sterilize the unlabeled Petri dishes. Make sure the dishes are placed so that appropriate steam circulation may occur.


  1. Use your pressure cooker or autoclave as directed by the manufacturer.
  2. Petri dishes are typically autoclaved for 15 to 20 minutes at a pressure of 15 psi at a temperature of 121°C (250°F). The precise time may change based on the load and autoclave you are using.
  3. The autoclaving procedure sterilizes the dishes by eradicating all bacteria on them.


  1. In the autoclave or pressure cooker, let the Petri dishes cool to room temperature. Wait until the temperature has decreased enough before opening the chamber.

Moisture Check:

  1. Check the Petri dishes to make sure there is no dampness or moisture present. Contamination might occur if there is any moisture on the dishes.

Pouring Agar (if applicable):

  1. Under aseptic circumstances (such as in a laminar flow hood or sterile environment), pour the sterilized agar medium onto the Petri dishes that have been labeled if you are using agar.
  2. Before continuing, let the agar in the Petri dishes firm.


  1. Until you’re ready to use them in your studies, keep the prepared, disinfected Petri plates in a clean, sterile environment. To avoid contaminating them, keep them covered with their lids.


Open the Petri dishes in a controlled setting, such as a laminar flow hood or a spotless workspace, when you’re ready to use them. Make careful to use sterile procedures throughout the entire experiment.

These procedures can help you properly disinfect and prepare your Petri plates for investigations, reducing the chance of contamination and ensuring accurate findings. To keep both you and those around you safe while performing these tasks, always follow the lab safety and biosafety procedures.

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