CRITERION™ TERGITOL 7 BROTH

Cat. no. C7910 CRITERION™ Tergitol 7 Broth 36gm
Cat. no. C7911 CRITERION™ Tergitol 7 Broth 500gm
Cat. no. C7912 CRITERION™ Tergitol 7 Broth 2kg
Cat. no. C7913 CRITERION™ Tergitol 7 Broth 10kg
Cat. no. C7914 CRITERION™ Tergitol 7 Broth 50kg

INTENDED USE

Hardy Diagnostics CRITERION™ Tergitol 7 Broth is used for enumerating and differentiating coliform bacteria.

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

Tergitol 7 (sodium heptadecyl sulfate) Broth is selective for Escherichia coli and members of the coliform group. This medium inhibits the growth of gram-positive microorganisms and spore-forming gram-negative microorganisms while allowing for superior recovery of coliforms.(4) According to the formula published by Chapman, the addition of Tergitol 7 to the medium consisting of proteose peptone no. 3, yeast extract, lactose, and bromothymol blue permitted unrestricted development of all coliform bacteria and inhibited development of gram-negative spore-formers as well as gram-positive microorganisms. He found the difference between Escherichia coli and other coliforms to be distinct in this medium since E. coli turns the media yellow while other coliforms turn the media blue. Bromothymol blue is incorporated as a pH indicator which indicates the fermentation of lactose.

Tergitol 7 Broth contains yeast extract and proteose peptone no. 3 as sources of nutrients. Lactose is the fermentable carbohydrate source. Bromothymol blue is incorporated as a pH indicator which indicates the fermentation of lactose.

FORMULA

Gram weight per liter: 18gm/L
Lactose 10.0gm
Proteose Peptone No. 3 5.0gm
Yeast Extract 3.0gm
Bile Salts No. 3 1.0gm
Tergitol 7 0.1gm
Bromothymol Blue 0.025gm

Final pH 6.9 +/- 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.

Store the prepared culture media at 2-30ºC.

PRECAUTIONS

METHOD OF PREPARATION FOR DEHYDRATED CULTURE MEDIA

1. Suspend 18.0gm of the dehydrated culture media in 1 liter of distilled or deionized water.

2. Heat as necessary and mix to dissolve completely.

3. Autoclave at 121ºC. for 15 minutes.

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, etc., are not provided.

QUALITY CONTROL

Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Escherichia coli
ATCC ® 25922
A 18-48hr 35°C Aerobic Growth; media turns yellow
Enterobacter aerogenes
ATCC ® 13048
A 18-48hr 35°C Aerobic Growth; media turns yellow
Enterococcus faecalis
ATCC ® 29212
B 18-48hr 35°C Aerobic Inhibited; no color change

User Quality Control

PHYSICAL APPEARANCE

CRITERION™ Tergitol 7 Broth powder should appear homogeneous, free-flowing, and beige in color. The prepared media should appear slightly opalescent, without precipitate, and green in color.

REFERENCES

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

2. Tille, P., et al. Bailey and Scott's Diagnostic Microbiology, C.V. Mosby Company, St. Louis, MO.

3. Isenberg, H.D. Clinical Microbiology Procedures Handbook, Vol. I, II & III. American Society for Microbiology, Washington, D.C.

4. Chapman, G.H. 1947. A superior culture medium for the enumeration and differentiation of coliforms. J. Bacteriol.; 53:504.

5. Chapman, G.H. 1951. A culture medium for detecting and confirming Escherichia coliin ten hours. Am. J. Public Health; 41:1381.

6. Mossel, D.A.A. 1962. An ecological investigation on the usefulness of two specific modifications of Eijkman's test as an element of the methods for the detecting of faecal contamination of foods. J. Appl. Bacteriol.; 25:20.

7. Speck, Marvin L. 1992. Compendium of Methods for the Microbiological Examination of Foods, 3rd ed. American Public Health Association, Washington, D.C.

8. MacFaddin, J.F. 1985. Media for Isolation, Cultivation, Identification, Maintenance of Bacteria, Vol. I. Williams & Wilkins, Baltimore, MD.


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

062716gr