Potato Dextrose Agar (PDA) is used for the cultivation of fungi. Potato Dextrose Agar (PDA) is a general purpose medium for yeasts and molds that can be supplemented with acid or antibiotics to inhibit bacterial growth. It is recommended for plate count methods for foods, dairy products and testing cosmetics. PDA can be used for growing clinically significant yeast and molds. The nutritionally rich base (potato infusion) encourages mold sporulation and pigment production in some dermatophytes.
Principle of Potato Dextrose Agar (PDA)
Potato Dextrose Agar is composed of dehydrated Potato Infusion and Dextrose that encourage luxuriant fungal growth. Agar is added as the solidifying agent. Many standard procedures use a specified amount of sterile tartaric acid (10%) to lower the pH of this medium to 3.5 +/- 0.1, inhibiting bacterial growth. Chloramphenicol acts as a selective agent to inhibit bacterial overgrowth of competing microorganisms from mixed specimens, while permitting the selective isolation of fungi.
Note: Do not reheat the acidified medium, heating in the acid state will hydrolyze the agar.
Uses of Potato Dextrose Agar (PDA)
- Potato Dextrose Agar is used for the detection of yeasts and molds in dairy products and prepared foods.
- It may also be used for the cultivation of yeasts and molds from clinical specimens.
- Potato Dextrose Agar with TA (Tartaric Acid) is recommended for the microbial examination of food and dairy products.
- Potato Dextrose Agar with Chlortetracycline is recommended for the microbial enumeration of yeast and mold from cosmetics.
- Potato Dextrose Agar with Chloramphenicol is recommended for the selective cultivation of fungi from mixed samples.
Composition of Potato Dextrose Agar (PDA)
Preparing Ourself
| Composition | |
|---|---|
| Potato infusion | 200 gm |
| Dextrose | 20 gm |
| Agar | 20 gm |
| Distilled water | 1 liter |
Note: 200 gm of potato infusion is equivalent to 4.0 gm of potato extract.
Preparing from Commercial Medium Powder
| Preparing | |
|---|---|
| Commercial PDA Powder (20 gm dextrose, 15 gm agar, and 4 gm potato starch) | 39 gm |
| Distilled water | 1 liter |
Procedure of Potato Dextrose Agar (PDA)
Preparing Ourself
- To prepare potato infusion, boil 200 g sliced, unpeeled potatoes in 1 liter distilled water for 30 min.
- Filter through cheesecloth, saving effluent, which is potato infusion (or use commercial dehydrated form).
- Mix with Dextrose, Agar and Water and boil to dissolve.
- Autoclave 15 min at 121°C.
- Dispense 20-25 ml portions into sterile 15 × 100 mm petri dishes.
- Final pH, 5.6 ± 0.2.
Preparing from Commercial Medium Powder
- Add 39 gm of Commercial PDA Powder to 1 Litre of Distilled water.
- Boil while mixing to dissolve.
- Autoclave 15 min at 121°C.
In addition, Potato Dextrose Agar with Chlortetracycline contains:
| Chlortetracycline | 40.0 mg |
In addition, Potato Dextrose Agar with Chloramphenicol contains:
| Chloramphenicol | 25.0 mg |
Final pH of 5.6 +/- 0.2 at 25 degrees C.
In addition, Potato Dextrose Agar with TA contains:
| Tartaric Acid | 1.4 gm |
Final pH of 3.5 +/- 0.3 at 25 degrees C.
Colony Characteristics on Potato Dextrose Agar (PDA)
After sufficient incubation, isolated colonies should be visible in the streaked areas and confluent growth in areas of heavy inoculation.
Aspergillus flavus: Powdery masses of yellow-green spores on the upper surface and reddish-gold on the lower surface.
Penicillium chrysogenum: Olivaceous green with sterile white margin on the upper surface and Orange to red, wrinkled on the lower surface.
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Can we make the PDA by adding the chloramphenicol? Is it before sterilization or after sterilization?
You can add chloramphenicol with an average of 0.05-1g to PDA medium before autoclaving because the chlramphenicol is not be affected by heating and then put the medium in autoclave at 121 0 C for 20-30 minutes.
To what volume of PDA can I use the recommended quantity of Chloramphenicol?
Any risks with using DRBC for TYM testing? Is there any data on aspergillus sp. inhibition due to the use of chloramphenicol?
Is it normal to change the smell after pouring the culture medium into distilled water?
What is the hypothesis of PDA media
After streaking, my observation was a pink and orange fungi.. They looked slimy….. What could possibly be the names of these fungi
Trichothecium or yeast
What is importance of PDA and TSA for growing soil bacteria?
Potato dextrose aagar wchic is used to growa of fungi but for bacteria which is used to nutritient aagar
How can I prepare a potatoes destrose agar with powder without boiling the Irish to remove the fission?
what is the role calcium chloride ,ammonium sulphate,magnesium sulphate in the PDA media
Does PDA works on all fungi?
almost yes. but there is some fungi can be optimum in other media PDA
Is there an article where i can reference fungal growth depending on species? We have multiple mold growth on our plate and there only limited visual sample reference to identify characteristics. There we were bright orange fungi with white spores grew on our plate.
same as mine. could you tell what was it?
why is fungi incubated on the bench and not in the incubator
what difference potato infusion and potato starch.
why the gram is different
We are using our auger for air tests. Does this need to be at room temp before we set it out and how long is the incubation? 5 days?
Explain to me how much tartaric I must weigh by 50ml distell water Nd how much PDA I must weigh by 100ml water plz,for a pH of 3.5
Hi !!Janine
answering your question do you recognize this formula
[C1V1=C2V2 ]
PDA
C1=mass of PDA on package
V1 =volume of PDA on package (1000ml)
C2=REQUIRED mass
V2=volume you preparing for (100ml)
Did anyone discover new agar media to grow cercospora
Hi, may I kniw what is the different of PDA and Sabouraud Dextrose Agar? They seem serve the same function.
I would like to ask if you prepared the PDA and refrigerate for 2 days. Does the PDA will spoil?
Only if contaminants are present on the agar. It will eventually dry out.
What is the reason behind pigmentation by fungus in Potato Dextrose Agar????
it is help in prepared practical record’s
How long doea it take for the potato dextrose agar to dehydrated when left open? This is for our research thanks!