How to prepare PDA media dishes – step by step

Step 1: Materials Collection
Gather the following materials:

PDA (Potato Dextrose Agar) media powder
Sterilized distilled water
Glass flask or beaker
PE disposable Petri dishes 90mm or 65mm
Laminar flow hood
Autoclave for sterilizing the PDA media
Paper towel and tinfoil

Step 2: Preparation of PDA Media
In a glass flask or beaker, add 500ml of sterilized distilled water. Slowly add 20g of PDA media powder while continuously stirring until the media is fully dissolved.

Step 3: Sterilization of PDA Media
Prepare a filtered cap for the flask, use rolled up kitchen towel in the opening of the flask and cover that with tin foil. Place the flask containing the PDA media into an autoclave and sterilize for 45 minutes. After sterilization, allow the media to cool but still warm enough to be poured. if you wait too long the media will solidify.

Step 4: Transfer of PDA Media into PE Disposable Petri Dishes
In the sterile airflow of a laminar flow hood, transfer the PDA media into the PE disposable Petri dishes. Fill each dish to approximately 1/3 of its capacity. Gently tap the dishes to distribute the media evenly and eliminate air bubbles. Leave to cool completely in the sterile airflow until the media has solidified.

Step 5: Storage of Petri Dishes
After the media has solidified, place the dishes in a sterile zip lock bag. Store the dishes in a cool, dark location.

Note: Sterile techniques must be followed at all times during handling of the media and Petri dishes to prevent contamination.

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