A Plate of Information on Petri Dishes

Petri dishes are shallow cylindrical dishes with loose coverings, usually made from glass or plastic. These are used by microbiologists in culturing bacterial, animal, fungal, or plant cells. The German bacteriologist Julius Richard Petri invented it in 1877 while working as an assistant to Robert Koch.

Petri dishes made from glass can be used more than once. But first, they should be heated in a hot air oven at a temperature of 160 degrees for around one hour, before they can be reused. Petri dishes made from plastic, on the other hand, must be disposed of after single use.

Petri dishes are usually made from polystyrene glass. This glass is sterilized after molding either by irradiation or treatment with ethylene oxide, to ensure sanitation as Petri dishes are very important in laboratory processes.

In microbiology, Petri dishes are lined with war liquid agar to create so-called agar plates. The dish is also filled with a mix of nutrients, salts and amino acids, and occasionally, antibiotics. The plate is used after the agar solidifies, and during which the dish is ready to receive microbe-laden samples.

Most Petri dish models have rings on the lids and bases so they can be stacked and not off one another. Multiple Petri dishes can also be inserted into a plastic container to create what a multi-well plate. One such type of the multi-well plate is the microtiter plate or microplate. It is a highly modified multi-well Petri dish plate.

Aside from making agar plates, Petri dishes without any added linings may also be used for plant germination, observing small animal or microorganism behavior, and cell cultures. They can also be used bare for any common laboratory practice such as drying fluids in the heat oven, as well as for carrying and storing cell and microorganism samples.