Potato Dextrose Agar (PDA), USP

Cat. no. H51 Potato Dextrose Agar, USP, 15x150mm Plate, 68ml 10 plates/bag
Cat. no. L90 Potato Dextrose Agar, USP, 20x125mm Tube, 10ml

20 tubes/box
Cat. no. Q29 Potato Dextrose Agar, USP, 20x125mm Tube, 18ml Deep

20 tubes/box
Cat. no. U294 Potato Dextrose Agar, USP, 8 oz. Bottle, 200ml 12 bottles/box
Cat. no. U376 Potato Dextrose Agar, USP, 500ml Polycarbonate Bottle, 500ml 10 bottles/box
Cat. no. U379 Potato Dextrose Agar, USP, 1L Polycarbonate Bottle, 1000ml 10 bottles/box
Cat. no. W60 Potato Dextrose Agar, USP, 15x100mm Plate, 26ml 10 plates/bag

INTENDED USE

Hardy Diagnostics Potato Dextrose Agar (PDA), USP is recommended for the cultivation of yeast and mold, and for the inducement of sporulation in non-clinical samples. Potato Dextrose Agar (PDA), USP is formulated as outlined by the U.S. Pharmacopoeia for the preparation of test strains used in microbial enumeration tests.(3)

This product is not intended to be used for the diagnosis of human disease.

SUMMARY

The Food and Drug Administration (FDA), the American Public Health Association (APHA), and the Association of Analytical Chemists (AOAC) recommend Potato Dextrose Agar for use in plate counts of yeast and mold cultures for the examination of dairy products and foods.(1,2,4,5) Potato Dextrose Agar is also recommended by the U.S. Pharmacopeia for the preparation and maintenance of test strains used for microbial enumeration tests as outlined in USP <61> and <62>.(3)

Potato Dextrose Agar, USP consists of potato infusion and dextrose. Potato infusion provides a nutrient base for luxuriant growth and sporulation of most fungi. Dextrose is an energy source. Agar is the solidifying agent.

FORMULA

Ingredients per liter of deionized water:*

Infusion from Potatoes 200.0gm
Dextrose 20.0gm
Agar 15.0gm

Final pH 5.6 +/- 0.2 at 25oC.

* Adjusted and/or supplemented as required to meet performance criteria.

Prepared in accordance with USP <62>.(3)

STORAGE AND SHELF LIFE

Storage: Upon receipt, store plated media (Cat. no. H51 and W60) at 2-8ºC away from direct light. Upon receipt, store tube (Cat. no. L90 and Q29) and bottle (Cat. no. U294, U376, and U379) media at 2-30ºC away from direct light. Media should not be used if there are any signs of deterioration (shrinking, cracking, or discoloration), contamination, or if the expiration date has passed. Product is light and temperature sensitive; protect from light, excessive heat, moisture, and freezing.

PRECAUTIONS

PROCEDURE

Before Use: The medium should be warmed to room temperature and the surface should be dry prior to inoculating.

For re-melting solid tube and bottle media: Autoclave containers with slightly loose caps at 121ºC for 1-3 minutes or until melted. Do not heat media longer than 3 hours at 45-50ºC. Alternatively, solid agar in capped containers can be racked and placed in a covered, boiling waterbath (100ºC) before use. There should be enough water in the waterbath to reach the top of the media line. A covered waterbath will maintain consistent temperature of the media until melted. Cool media to 45-50ºC and aseptically dispense into sterile containers. Note: Sterile solidified media can be remelted only once. In addition, the use of microwaves to melt media is not advised.

Preparation of Test Strains: Use stable standardized suspensions of test strains per reference method. Use appropriate diluent for making test suspensions and use suspensions within the specified time period or maintain under appropriate storage practices.(3)

Inoculate the surface of the medium and incubate aerobically at 20-25ºC for 5-7 days or until good sporulation is achieved. During incubation, caps should remain loose on tube or flask cultures to ensure adequate air circulation.

INTERPRETATION OF RESULTS

Consult listed references for information regarding the interpretation of growth of fungal species and for performing microscopic examinations.(1-5)

LIMITATIONS

For proper identification of fungi, microscopic examination and evaluation of morphological structures is required.

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as loops, swabs, applicator sticks, other culture media, incinerators, and incubators, etc., as well as serological and biochemical reagents, are not provided.

QUALITY CONTROL

Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Trichophyton mentagrophytes
ATCC® 9533**
G 5-7 days 20-25°C Aerobic Growth; may take up to 7 days
Trichophyton rubrum
ATCC® 28188**
G 3-4 weeks 20-25°C Aerobic Growth seen in 7 days; may take 3-4 weeks for red color on reverse side of colony to be visible
Aspergillus brasilliensis
ATCC® 16404
J 1-5 days 20-25°C Aerobic Growth; may take up to 5 days
Candida albicans
ATCC® 10231
J 1-3 days 20-25°C Aerobic Growth; may take up to 3 days

**Not tested with U376 and U379.
Tested in accordance with USP <61>.(3)

USER QUALITY CONTROL

Physical Appearance

Potato Dextrose Agar, USP should appear slightly opalescent and light amber in color.

T. mentagrophytes growing on Potato Dextose Agar

Trichophyton mentagrophytes (ATCC® 9533) growing on Potato Dextrose Agar, USP (Cat. no. W60). Incubated aerobically for 7 days at 20ºC.

T. mentagrophytes growing on Potato Dextose Agar

Showing red color on reverse side of Trichophyton rubrum (ATCC® 28188) growing on Potato Dextrose Agar, USP (Cat. no. W60). Incubated aerobically for four weeks at 20ºC.

Potato Dextrose Agar

Uninoculated plate of Potato Dextrose Agar, USP (Cat. no. W60).

REFERENCES

1. American Public Health Association. 2012. Standard Methods for the Examination of Dairy Products, 22nd ed. APHA, Washington, D.C.

2. APHA Technical Committee on Microbiological Methods for Foods. 2001. Compendium of Methods for the Microbiological Examination of Foods, 4th ed. APHA, Washington, D.C.

3. The U.S. Pharmacopeial Convention. USP-NF: U.S. Pharmacopoeia National Formulary . Rockville, MD.

4. Association of Official Analytical Chemists. 2012. Official Methods of Analysis , 19th ed. AOAC, Washington, D.C.

5. U.S. Food and Drug Administration. Bacteriological Analytical Manual. AOAC, Arlington, VA. http://www.fda.gov/Food/FoodScienceResearch/LaboratoryMethods/ucm2006949.htm


ATCC is a registered trademark of the American Type Culture Collection.

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