Petri dishes for cultures

The Petri dish is a small, low, flat cylindrical box made of plastic or glass.

Diameter ranges from approximately 60 mm to 150 mm.

Height from approximately 14 to 20 mm.

The Petri dish is used in microbiology for bacterial growth or in biology for the growth of cell or plant cultures.

The plate cover may have aeration or ventilation notches which, by preventing the plate from being completely closed, favor the passage of air, which is necessary in most cases for bacterial growth. Ventilation avoids the formation of condensation and prevents the passage of other microorganisms that could contaminate the soil.

The non-ventilated lid, without ventilation notches, prevents the agar from drying out during incubation and reduces gas exchange with the outside. It is therefore ideal for anaerobic crops.

In the case of media containing agar, the sterile plate is filled with loose culture medium which solidifies as it cools and forms a solid, smooth layer on which to proceed with cultures.

The media are stored inverted so that the condensation that forms during cooling does not fall onto the soil, altering it or altering any colonies grown on it.