Yeasts and moulds · General fungal agar
Potato Dextrose Agar – classic agar for fungi
Potato Dextrose Agar (PDA) is the classic medium for the cultivation, count and identification of yeasts and moulds. It supports good sporulation and pigment formation, which helps with the identification of moulds. Acidified with tartaric acid, it is used for yeast and mould counts.
- Good sporulation and typical pigments
- For cultivation and identification of fungi
- Can be acidified or made selective
How Potato Dextrose Agar works
Potato infusion and dextrose provide nutrients that promote the growth and sporulation of fungi. For counts, the pH is lowered to about 3.5 with sterile tartaric acid, or an antibiotic is added, so that bacteria are suppressed. Plates are incubated at 20–25 °C.
Typical colony appearance
| Organism | Colonies |
| Aspergillus brasiliensis | White mycelium with black spores |
| Yeasts | Cream colonies |
Technical data
| Preparation | 40 g/L; boil to dissolve, autoclave 121 °C 15 min |
| Final pH | 5.6 ± 0.2 |
| Incubation | 20-25 °C, 2-3 d (QC) |
| Storage | Dry, dark place; keep the container tightly closed |
| Shelf life | 3 years unopened |
Applications and practical notes
General fungal media are used for the cultivation, maintenance and identification of yeasts and moulds in food, environmental and research laboratories, as described for example in FDA BAM Chapter 18. Typical applications include:
- Cultivation and maintenance of yeasts and moulds
- Morphological identification of fungi
- Environmental and air monitoring
- Teaching and research laboratories
Working with Potato Dextrose Agar: Do not reheat acidified medium, because the agar loses its gel strength at low pH.
Good practice with dehydrated media: keep the bottle tightly closed in a cool, dry place, weigh the powder quickly to avoid moisture uptake, and use fresh distilled or deionised water. Check the pH of each new batch after preparation and before use, and label prepared media with the date. Performance of each lot can be verified with reference strains according to ISO 11133, the standard for the preparation, production, storage and performance testing of culture media.
About yeast and mould methods: in the food chain, yeasts and moulds are counted by spread plating on DRBC Agar for products with a water activity above 0.95 according to ISO 21527-1, and on DG18 Agar for drier products according to ISO 21527-2. The FDA BAM Chapter 18 describes similar plate count methods. In pharmaceutical microbiology, the total yeast and mould count (TYMC) and the test for Candida albicans use Sabouraud media according to EP 2.6.12 / 2.6.13 and USP <61> / <62>. COLO.Science offers counting media, identification media, supplements and reference strains for every step.
Complete sets from one supplier: COLO.Science supplies culture media, supplements, rapid tests, identification kits and QC strains as complete sets for the method you follow. Send us your sample types and standards, and we will prepare an offer with the matching products and documentation.
Potato Dextrose Agar is supplied by COLO.Science in the pack sizes listed under Ordering information. For larger quantities, regular deliveries or method-specific sets that include Potato Dextrose Agar, please send us a request. With every delivery of Potato Dextrose Agar you receive the lot number and expiry date, and on request we send the available documentation for Potato Dextrose Agar.
Where Potato Dextrose Agar fits in yeast and mould testing
- Food and feed counts – DRBC Agar for aw > 0.95 (ISO 21527-1) and DG18 Agar for aw ≤ 0.95 (ISO 21527-2); alternatives: Rose Bengal Chloramphenicol, PDA with chloramphenicol, YGC for dairy products
- Pharmaceutical products – Sabouraud Dextrose Agar and Broth for TYMC and the Candida albicans test (EP 2.6.12 / 2.6.13, USP <61> / <62>)
- Cultivation and identification – PDA, Malt Extract and Czapek-Dox Agar for moulds; Corn Meal, chromogenic Candida and BIGGY Agar, Yeast Nitrogen Base for yeasts
- Fermentation and QC – WL Nutrient, Wort Agar and YPD for brewing and culture yeasts; C. albicans and A. brasiliensis reference strains for media testing
See the complete yeast and mould set in the Microbiology Catalogue →
Ordering information
| Product | COLO code | Pack |
|---|---|---|
| Potato Dextrose Agar (PDA) | PRO7462 | 500 g |
Product notice: preparation, storage conditions and shelf life are given on the label. Technical data on this page are for orientation; the label and the lot documentation apply. B2B prices are quoted net, excluding VAT.
Sales and technical support
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Quotations and technical support for culture media and microbiology products across our international sales territory. B2B prices are net, excluding VAT.
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Need the complete set for your method?
Send the sample type, target organism and the standard you follow. COLO.Science will put together the media, supplements, QC strains and confirmation tests for the whole procedure.
