CRITERION™ MALT EXTRACT AGAR

Cat. no. C6200 CRITERION™ Malt Extract Agar 110.5gm
Cat. no. C6201 CRITERION™ Malt Extract Agar 500gm
Cat. no. C6202 CRITERION™ Malt Extract Agar 2kg
Cat. no. C6203 CRITERION™ Malt Extract Agar 10kg
Cat. no. C6204 CRITERION™ Malt Extract Agar 50kg

INTENDED USE

Hardy Diagnostics CRITERION™ Malt Extract Agar is recommended for the isolation, cultivation and maintenance of yeasts and molds.

This dehydrated culture medium is a raw material intended to be used in the making of prepared media products, which will require further processing, additional ingredients, or supplements.

SUMMARY

Fungal testing is conducted to identify the fungal impact on manufacturing processes, avoid structural damage that can accompany mold growth, as well as recognize fungal isolates that may compromise human health. In addition to being the etiologic agents for disease, fungi have the potential to produce allergens, irritants, and in some cases potentially toxic substances (mycotoxins), which can induce an allergic response, cause asthma attacks, and irritate the eyes, skin, throat, and lungs of susceptible individuals.(8) CRITERION™ Malt Extract Agar is used as a general purpose growth media to isolate and cultivate yeasts and molds from clinical samples as well as a wide range of environmental sources.

CRITERION™ Malt Extract Agar, based on the formula recommended by Thom and Church, is designed to contain the proper formulation of carbon, protein and nutrient sources essential for yeast and mold growth.(7) Dextrose is added to the medium to provide a carbon and energy source for fungi. Additionally, CRITERION™ Malt Extract Agar contains digests of animal tissues (peptones) which provide a nutritious source of amino acids and nitrogenous compounds for the growth of mold and yeasts. The pH is adjusted to approximately 5.5 in order to enhance the growth of fungi and to slightly inhibit bacterial growth commonly found as environmental contaminants.(6)

FORMULA

Gram weight per liter: 55.25gm/L
Malt Extract 20.0gm
Dextrose 20.0gm
Peptone 2.25gm
Agar 13.0gm

Final pH 5.5 +/- 0.2 at 25ºC.

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

STORAGE AND SHELF LIFE

Store the sealed bottle(s) containing dehydrated culture medium at 2-30ºC. Dehydrated culture medium is very hygroscopic. Keep lid tightly sealed. Protect dehydrated culture media from moisture and light. The dehydrated culture media should be discarded if it is not free-flowing or if the color has changed from its original beige color.

Store the prepared culture media at 2-8ºC.

PRECAUTIONS

METHOD OF PREPARATION FOR DEHYDRATED CULTURE MEDIA

1. Suspend 55.25gm of the dehydrated culture media in 1 liter of distilled or deionized water. Stir to mix thoroughly.

2. Heat to boiling to dissolve completely. Do not overheat.

3. Sterilize in the autoclave at 121ºC. for 15 minutes.

4. Cool to 45-50ºC. and pour into sterile petri dishes or tubes.

PROCEDURE AND INTERPRETATION OF RESULTS

For information on procedures and interpretation of results, consult listed references or refer to the prepared media Instructions for Use (IFU) for Cat. No. W28.

LIMITATIONS

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as autoclaves, incinerators, and incubators, etc., are not provided.

QUALITY CONTROL

Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Aspergillus brasiliensis
formerly A. niger
ATCC® 16404

G 1-7 days 15-20°C Aerobic Growth
Candida albicans
ATCC® 10231
A 1-7 days 35°C Aerobic Growth
Saccharomyces cerevisiae
ATCC® 9763
A 1-7 days 35°C Aerobic Growth
Escherichia coli
ATCC® 25922
A 1-7 days 35°C Aerobic Partial to complete inhibition

User Quality Control

PHYSICAL APPEARANCE

CRITERION™ Malt Extract Agar powder should appear homogeneous, free-flowing, and beige in color. The prepared media should appear clear, and light to medium amber in color.

REFERENCES

1. Jorgensen., et al. Manual of Clinical Microbiology, American Society for Microbiology, Washington, D.C.

2. Atlas, R.M. 1995. Handbook of Microbiological Media for the Examination of Food. CRC Press, Boca Raton, LA.

3. Koneman, E.W., et al. Color Atlas and Textbook of Diagnostic Microbiology, J.B. Lippincott Company, Philadelphia, PA.

4. APHA Technical Committee on Microbiological Methods for Foods. Compendium of Methods for the Microbiological Examination of Foods, APHA, 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.

6. Ajello, et al. 1963. CDC Laboratory Manual for Medical Mycology, PHS Publication No. 994. U.S. Gov't Printing Office, Washington, D.C.

7. Thom, C. and M.B. Church. 1926. The aspergilli. Williams & Wilkins Co., Baltimore, MD.

8. U.S. Environmental Protection Agency. 2002. "A brief guide to mold, moisture, and your home." Internet: www.epa.gov/iaq/molds/moldguide.html.

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

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