Petri Dishes, Disposable

Product Details

Polystyrene. Sterile. Package of 20.

How to Make Agar Petri Dishes

The steps in making agar Petri dishes should be carefully followed to maintain sterile conditions from the onset of an experiment. (This procedure assumes that the Petri dishes and the media have been sterilized.)

1. If the agar has solidified, stand the tubes (or other media container) in a warm water bath until the media melts to liquid form with no lumps remaining.

2. Wet down the working area with a sponge and disinfectant. Avoid air drafts while plating. The less people walk around the work area the better.

3. Line up the Petri dishes near the edge of the table in a single file for quick and easy access.

4. Use a Bunsen burner and position the burner for minimal distance to the Petri dishes.

5. Use one of the melted agar tubes. Remove the cap or plug and flame the mouth of the test tube by passing it through the flame of the Bunsen burner to sterilize therim of the test tube.

6. Only open the Petri dish to pour the liquid media into the dish. Lift the cover straight up and keep it straight above the bottom half of the dish. Do this while trying not to
create any wind currents.

7. Pour the liquid media into the Petri dish and cover the bottom half of the plate.

8. Replace the cover on the dish immediately and then gently swirl (if necessary) the dish so that the medium is evenly distributed in a thin film.

9. Let the dish sit undisturbed until the media solidifies.

10. When all the poured dishes have solidified, invert the dishes to prevent condensation from falling back onto the agar.

11. Refrigeration can help prevent contamination. Dishes can be stored in a refrigerator for a week or so before use.