Potato Dextrose Agar

EMD Cat. No. 1.10130.0500/5007
500 g, 5 kg


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 USP 30.

Potato Dextrose Agar is not used in any of the tests listed in USP 30 (Chapter <62> but is listed in that chapter for reference. In Chapter (62), the USP 30 lists all media that are mentioned in Chapter <61>. There is a test in Chaper <61> that lists Potato Dextrose Agar as an acceptable growth promotion medium.

Click here for information about harmonization of USP/EP chapters on Microbiological Examination of Non-sterile Products (formerly called Microbial Limits Test).


Additives


EMD Cat. No. Product Pack Size
TX0010-4 L(+)-Tartaric acid 250 g



Mode of Action Preparation
Experimental Procedure and Evaluation Quality Control
Typical Composition (g/liter) Literature
Picture/Image


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 (g/liter)
 Potato infusion 4.0 (infusion from 200 g potatoes); D(+)glucose 20.0; agar-agar 15.0.
Preparation
 Suspend 39 g/liter, autoclave (15 min at 121 °C).
pH: 5.6 ± 0.2 at 25 °C.
 If the pH has to be adjusted to 3.5, add approx. 14 ml of a sterile 10 % tartaric acid solution/liter at a temperature of 45-50 °C.
 The plates are clear and yellowish-brown.
  •   Do not reliquefy.
    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.
    Quality control

    Test strains
    		 Growth
    Geotrichum candidum DSM 1240
         		good / very good
    Penicillium commune ATCC 10428
         		medium / good
    Trichophyton ajelloi ATCC 28454
         		medium / good

    Quality control (spiral plating method)

    Test strains
    		 Inoculum (cfu/ml)
         		Recovery rate %
    Candida albicans ATCC 10231
         		10 - 100
         		≥70
    Saccharomyces cerevisiae ATCC 9763
         		10 - 100
         		≥70
    Rhodotorula mucilaginosa DSM 70403
         		10 - 100
         		70
    Asperfillus Niger ATCC 16404
         		10 - 100
         		≥ 50


    Literature

    BEEVER, R.E., a. BOLLARD, E.G.: The nature of the stimulation of fungal growth by potato extract. J. Gen. Microbiol., 60; 273-279 (1970).
     American Public Health Association: Compendium of methods for the microbiological examination of foods. 3rd ed., 1992.

    United States Pharmacopeia 30

    <61> Microbiological Examination of Non-sterile Products: Microbial Enumeration Tests (USP 30, page 89).
    <62> Microbiological Examination of Non-sterile Products: Tests for Specified Microorganisms (USP 30, page 93).

    European Pharmacopeia 6 (Ph. Eur)
    2.6.12 Microbiological Harmonization of Non-sterile Products - Microbial Enumeration Test
    2.6.12 Microbiological Harmonization of Non-sterile Products - Tests for Specified Microorganisms


    Aspergillus niger



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