Nutrient Agar in Petri Dishes

Ready-poured nutrient agar plates (petri dishes), providing a convenient means of culturing microorganisms, as no preparation of the culture medium is required. They provide a general-purpose media, suitable for growing a wide range of microorganisms (bacteria and fungi). Shelf life is approx. 4-6 weeks if stored at room temperature. It is NOT advisable to store in a refrigerator, due to the formation of condensation inside the petri dish, leading to a wet agar surface. Petri dish size: 90 mm diameter. Supplied in a plastic sleeve of 10 aseptic plates (manufactured in a cleanroom facility and quality checked at several stages, right up to dispatch).

Q = Can you provide more information about the Ready Prepared Nutrient Agar in petri dishes.
A = These are ready-poured nutrient agar plates (petri dishes), offering a convenient means of culturing microorganisms, as no preparation of the culture medium is required.
 They provide a general purpose media, suitable for growing a wide range of microorganisms (bacteria and fungi).

 The shelf life is approx. 4-6 weeks if stored at ambient room temperature (below 25oC). It is NOT advisable to store in a refrigerator due to the formation of condensation inside the petri dish, leading to a wet agar surface.

 Cultured petri dishes should be disposed of in the usual manner for used plates, by autoclaving within an autoclave bag or pouch.

 Specifications:

 • Size: 90mm diameter single vent plates
 • Media fill volume: Approx. 18ml
 • Pack Quantity: 10 plates

Q = Having made my agar powder into solution it will not melt again at 50oC, as required for a practical. How do I re-melt it?
A = This is a feature which is typical of agar media.
 Although it is a gel at room temperature and solidifies at around 30-40°C, it will remain firm at temperatures as high as 65°C or so and will often not melt again fully until the temperature reaches 85°C to 95oC (depending on type). This property is known as hysteresis.
 What you will probably need to do is to bring the solidified agar up to 85-95oC then allow it cool to 50oC, maintaining it there, at which temperature it should remain liquid. All this can be done in a water bath or 2 baths at different temperatures (or heat in a pan of water until it melts, then maintain at 50oC in a water bath).