Place a sterilized Petri dish on the lab table and keep it closed to prevent airborne contamination. Take the liquid agar solution and place the bottle neck over a low flame to sterilize the bottle opening to prevent cross-contamination.
Wear gloves when handling the sterilized agar bottle and the Petri dishes. Pour the agar into the Petri dish by slightly lifting the Petri dish lid. Pour enough agar to cover at least 1/8 of the bottom of the Petri dish. Quickly close the lid on the Petri dish.
Place the Petri dish on the lab table and allow it to cool at room temperature. Once the agar has cooled in the Petri dish then the agar is ready for the substance to be inserted.
Take the substance that will be introduced to the agar medium and insert it on to the agar. Spread the substance if needed. Ensure not to cross-contaminate the dish by slightly lifting the lid to add the substance.
Secure the Petri dish once the substance has been added. Incubate the substance by placing the Petri dish in a zip-locked bag. The ideal temperature for incubation is 90 degrees Fahrenheit.