CRITERION™ TRYPTONE GLUCOSE EXTRACT (TGE) AGAR

Cat. no. C7160 CRITERION™ Tryptone Glucose Extract Agar 48gm
Cat. no. C7161 CRITERION™ Tryptone Glucose Extract Agar 500gm
Cat. no. C7162 CRITERION™ Tryptone Glucose Extract Agar 2kg
Cat. no. C7163 CRITERION™ Tryptone Glucose Extract Agar 10kg
Cat. no. C7164 CRITERION™ Tryptone Glucose Extract Agar 50kg

INTENDED USE

Hardy Diagnostics CRITERION™ Tryptone Glucose Extract Agar is recommended for the cultivation and enumeration of microorganisms found in food, water, and dairy products.

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

In 1910, The American Public Health Association (APHA) issued its first publication entitled " Standard Methods of Milk Analysis," which recommended the use of Standard Nutrient Agar for estimating bacterial counts in milk and dairy products.(12) In 1935, Bower and Hucker outlined the composition of a medium for the bacteriological analysis of milk, and reported higher plate counts and larger colony sizes from routine milk grading laboratories.(1,2) Consequently, many researchers compared the performance of this medium, Tryptone Glucose Skim Milk Agar, to the more commonly used Nutrient Agar for estimating bacteria in milk samples and other dairy products.

In 1948, the American Public Health Association (APHA) adopted Tryptone Glucose Extract Agar for use in testing milk and dairy products; for many years, this medium became the standard for testing dairy and water products when supplemented with milk.(4) Tryptone Glucose Extract Agar is currently recommended by the Compendium of Methods for the Microbiological Examination of Foods for performing the heterotrophic plate count when testing bottled
water.(5)

CRITERION™ Tryptone Glucose Extract Agar is a non-selective medium containing pancreatic digest of casein, beef extract, and glucose, which provide vital amino acids, nitrogen, carbon compounds, carbohydrates, essential minerals, and trace substances to promote the growth of a variety of microorganisms. Agar is the solidifying agent.

FORMULA*

Gram weight per liter: 24.0gm/L
Pancreatic Digest of Casein 5.0gm
Beef Extract 3.0gm
Glucose 1.0gm
Agar 15.0gm

Final pH 7.0 +/- 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 light beige.

Store the prepared culture media at 2-8ºC.

PRECAUTIONS

METHOD OF PREPARATION FOR DEHYDRATED CULTURE MEDIA

1. Suspend 24.0gm of the dehydrated culture media in 1 liter of distilled or deionized water. Stir to mix thoroughly.

2. Heat to boiling to dissolve completely.

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

4. Cool to 45-50ºC. and aseptically dispense into sterile containers.

PROCEDURE AND INTERPRETATION OF RESULTS

For information on procedures and interpretation of results, consult listed references.

LIMITATIONS

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as autoclaves, incinerators, and incubators, pipettes, sterile diluent, spreaders, tubes, petri dishes, etc., are not provided.

QUALITY CONTROL

Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Escherichia coli
ATCC ® 25922
J 24-48hr 35°C Aerobic Growth
Staphylococcus aureus
ATCC ® 25923
J 24-48hr 35°C Aerobic Growth

User Quality Control

PHYSICAL APPEARANCE

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

REFERENCES

1. Bowers and Hucker. 1935. The composition of media for the bacteriological analysis of milk. Tech Bull. N.Y. State Agr. Expt. Sta. No. 228.

2. Bowers and Hucker. 1936. Further studies of the composition of media for the bacteriological analysis of milk. Am. J. of Public Health. Vol. 26.

3. Standard Methods of Milk Analysis, 6th ed. 1934.

4. Standard Methods for the Examination of Dairy Products. APHA, New York, N.Y.

5. Kim and Feng. 2001. In Downes and Ito (ed.), Compendium of Methods for the Microbiological Examination of Foods, 4th ed. 1992. APHA, Washington, D.C.

6. Standard Methods for the Examination of Water and Waste Water. APHA, Washington, D.C.

7. Association of Official Agricultural Chemists, 10th ed. p. 737; 1965.

8. Association of Official Analytical Chemists. Official Methods of Analysis, AOAC, Washington, D.C.

9. The Official Compendia of Standards. USP27-NF22. United States Pharmacopeial Convention, Rockville, MD.

10. Standard Methods for the Examination of Dairy Products, 16th ed. 1992. APHA, Washington, D.C.

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

12. Am. J. Pub. Hyg. 1910. 6:315-345.


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

062716gr