MALT EXTRACT AGAR

Cat. no. H57 Malt Extract Agar, 15x150mm Plate, 68ml 10 plates/bag
Cat. no. P93 Malt Extract Agar with Lecithin and Tween® 80, 15x60mm Contact Plate, 15ml 10 plates/bag
Cat. no. W28 Malt Extract Agar, 15x100mm Plate, 26ml 10 plates/bag
Cat. no. L128 Malt Extract Agar with 0.01% Chloramphenicol, 16x100mm Tube, 5.5ml slant 20 tubes/box
Cat. no. P80 Malt Extract Agar with Chloramphenicol, 15x60mm
Contact Plate, 15ml
10 plates/bag
Cat. no. W80 Malt Extract Agar with Chloramphenicol, 15x100mm
Plate, 26ml
10 plates/bag

INTENDED USE

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

Cat. no. P80 and P93 are not intended to be used for the diagnosis of human disease.

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) 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.

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, 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) Chloramphenicol is added to increase the inhibitory properties of Malt Extract Agar with Chloramphenicol (Cat. no. P80 and W80) to inhibit bacterial overgrowth while permitting successful selective isolation of fungi and yeasts. Malt Extract Agar with Lecithin and Tween® 80 can be used to test the efficacy of disinfection procedures.

FORMULA

Ingredients per liter of deionized water:*

Malt Extract Agar:
Malt Extract 20.0gm
Dextrose 20.0gm
Peptone 6.0gm
Agar 15.0gm

Final pH 5.5 +/- 0.3 at 25ºC.

In addition to the above ingredients,
Malt Extract Agar with Chloramphenicol contains 0.1gm of chloramphenicol per liter and Malt Extract Agar with Lecithin and Tween contains 5.0gm Tween and 0.7gm Lecithin per liter.

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

STORAGE AND SHELF LIFE

Storage: Upon receipt store plated media at 2-8ºC., away from direct light. Upon receipt store tubed/bottles 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

For Cat. nos. H57, L128, W28 and W80.

For Cat. nos. P93 and P80.

PROCEDURE

Specimen Collection: It is important to take proper cautions when cleaning mold contaminated areas, in order to limit exposure to mold and mold spores. It is recommended that while cleaning an area potentially contaminated with fungi that one wears a N-95 respirator, gloves, and goggles. For additional information consult the listed reference.(8)

1. Allow media to warm to room temperature, and the agar surface to dry before inoculating.

2. Using a needle, loop, or swab remove a small amount of mature growth from the area to be cultured. Inoculate and streak the sample as soon as possible after collection.

3. If the specimen to be cultured is on a swab, roll the swab over a small area of the agar surface. Streak for isolation with a sterile loop. If the specimen is collected on a loop or needle, inoculate the plate with fungi in two or three distinct places by pressing the inoculum onto the agar surface. Yeasts should be streaked for isolation using four quadrants.

4. Incubate plates in an inverted position. Consult listed references for more information on incubation time and temperature. (1,3,4,8) Once inoculated, media can be incubated aerobically at 25-35ºC. with increased humidity for four weeks or longer. Hardy Diagnostics MycoSeal™ product (Cat. no. SS9225) may be used to seal the plates to keep moisture from evaporating from the plated media, while still allowing atmospheric circulation

5. Examine plates for typical colonial and hyphal morphology and color.

Refer to the keyword "CSP Surface and Fingertip Monitoring - Contact Plates" on the Hardy Diagnostics Technical Document for more information regarding the method of use for Cat. no. P93, and P80 Contact Plates

INTERPRETATION OF RESULTS

Identification of fungi is performed by observing various aspects of colony morphology, characteristic microscopic structures, rate of growth, media which supports the organisms growth, and source of the specimen. Yeasts are identified by various biochemical tests. Consult the listed references for information regarding the identification and further testing of fungi and yeast cultures. (1,3,4,8)

LIMITATIONS

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as loops, other culture media, swabs, applicator sticks, 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
Malt Extract Agar: H57, P93, W28
Aspergillus brasiliensis
ATCC® 16404
G 2-7 days 15-30°C Aerobic Growth
Candida albicans
ATCC® 10231
A 24-48hr 15-30°C Aerobic Growth
Saccharomyces cerevisiae
ATCC® 9763
A 24-48hr 15-30°C Aerobic Growth
Malt Extract Agar with Chloramphenicol: L128, P80, W80
Aspergillus brasiliensis
ATCC® 16404
G 2-7 days 15-30°C Aerobic Growth
Candida albicans
ATCC® 10231
A 24-48hr 15-30°C Aerobic Growth
Saccharomyces cerevisiae
ATCC® 9763
A 24-48hr 15-30°C Aerobic Growth
Escherichia coli
ATCC® 25922
B 24-48hr 35°C Aerobic Partial to complete inhibition

* Consult appropriate regulatory agency for user QC requirements.

USER QUALITY CONTROL

PHYSICAL APPEARANCE

Malt Extract Agar should appear clear, slightly opalescent, and light to medium amber in color.

A. niger growing on Malt Extract Agar

Aspergillus brasiliensis (ATCC® 16404) growing on Malt Extract Agar (Cat. no. W28). Incubated aerobically for 7 days at 30ºC.

C. albicans growing on Malt Extract Agar

Candida albicans (ATCC® 10231) colonies growing on Malt Extract Agar (Cat. no. W28). Incubated aerobically for 48 hours at 30ºC.

S. cerevisiae growing on Malt Esctract Agar

Saccharomyces cerevisiae (ATCC® 9763) colonies growing on Malt Extract Agar (Cat. no. W28). Incubated aerobically for 48 hours at 30ºC.

Malt Esctract Agar

Uninoculated plate of Malt Extract Agar (Cat. no. W28).

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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