Potato Dextrose Agar, PDA 500g

Description

Potato Dextrose Agar is used for the cultivation, isolation and enumeration of yeasts and molds from foodstuffs and other materials.
This culture medium complies with the recommendations of the American Public Health Association for food (1992) and the United States Pharmacopeia.

Mode of Action
Carbohydrate and potato infusion (Beever and Bollard 1970) promote the growth of yeasts and molds while the low pH value partially inhibits the growth of the accompanying bacterial flora. If the medium is to be used for fungal counts, the pH should be adjusted to approximately 3.5. Fungi grow on this medium to develop typical morphology.

Typical Composition
Potato Infusion (infusion from 200g potatoes)          4 g/l
D(+)-Glucose (=Dextrose)                                       20 g/l
Agar-Agar                                                                15 g/l

Preparation
Suspend 39 g/l. Autoclave (15 min at 121 C). The appearance of the plates is clear and yellowish-brown.
The pH value at 25 °C is in the range of 5.4-5.8.
If the pH has to be adjusted to 3.5, add approx. 14 ml of a sterile 10 % tartaric acid solution/l at a temperature of 45-50 °C. After the tataric acid is added, do not re liquefy.

Experimental Procedure and Evaluation
Inoculate by the pour-plate method or by spreading the sample on the surface of the culture medium.
Incubation: up to 5 days at 28 °C aerobically.
Experimental procedure depends on the purpose for which the medium is used
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Storage
The product can be used for sampling until the expiry date if stored upright, protected from light and properly sealed at +15 °C to +25 °C.
After first opening of the bottle the content can be used up to the expiry date when stored dry and tightly
closed at +15 °C to +25 °C.

Disposal
Please mind the respective regulations for the disposal of used culture medium (e.g. autoclave for 20 min at 121 °C, disinfect, incinerate etc.).