Cat. no. C7060 CRITERION™ Tetrathionate Broth Base 92gm
Cat. no. C7061 CRITERION™ Tetrathionate Broth Base 500gm
Cat. no. C7062 CRITERION™ Tetrathionate Broth Base 2kg
Cat. no. C7063 CRITERION™ Tetrathionate Broth Base 10kg
Cat. no. C7064 CRITERION™ Tetrathionate Broth Base 50kg


Hardy Diagnostics CRITERION™ Tetrathionate Broth Base, with the addition of Iodine-Iodide Solution (Cat. no. Z129), is a selective enrichment medium for Salmonella spp., used for microbiological testing of foods such as, raw milk or other highly contaminated samples or specimens.(14,15)

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.


Muller first described use of Tetrathionate Broth for the cultivation and enrichment of Salmonella spp. Later modifications of the formula were done by Kauffman, Schaeffer, and Knox, et al.(12) Knox found Tetrathionate Broth to be inhibitory to commensal organisms while promoting growth of Salmonellae.(13)

CRITERION™ Tetrathionate Broth Base contains bile salts which act as a selective agent that inhibits gram-positive organisms and coliforms. Tetrathionate is formed with the addition of the Iodine-Iodide Solution (Cat. no. Z129) to the Tetrathionate Broth just prior to inoculation.(5) Proteose peptone acts as a nutritive base. The tetrathionate together with the sodium thiosulfate, iodide, and calcium carbonate, all work as selective agents to commensal fecal flora, but the most important of these is tetrathionate. Salmonella species that are capable of reducing tetrathionate will proliferate in this medium.(16)

CRITERION™ Tetrathionate Broth Base conforms to the formulation recommended by the American Public Health Association (APHA), the Food and Drug Administration (FDA), and The United States Pharmacopeia (USP).(8-11)


Gram weight per liter: 46.0gm/L
Sodium Thiosulfate 30.0gm
Calcium Carbonate 10.0gm
Proteose Peptone 5.0gm
Bile Salts 1.0gm

Final pH 8.4 +/- 0.2 at 25ºC.

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


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 white.

Store the prepared culture media at 2-8ºC.



1. Suspend 46.0gm of the dehydrated culture media in 1 liter of distilled or deionized water. Stir to mix thoroughly.

2. Heat as necessary to dissolve completely.

3. Do not autoclave.

4. Cool to 45-50ºC.

5. Aseptically dispense 10ml per sterile tube.

6. Refrigerate until use.


For information on procedures and interpretation of results, refer to the prepared media Instructions for Use (IFU) for Cat. No. K65.


The recovery of many Salmonella spp. is greatly jeopardized if stool specimens remain unpreserved for more than three hours before processing. If there is to be a delay in processing, the specimen should be inoculated onto an appropriate transport medium and refrigerated until further testing.


Standard microbiological supplies and equipment such as autoclaves, incinerators, Iodine-Iodide Solution (Cat. no. Z129), and incubators, etc., are not provided.


Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Salmonella enterica
ATCC ® 14028
I 18-24hr 35°C Aerobic Growth on HE or XLD upon subculture
Escherichia coli
ATCC ® 25922
I 18-24hr 35°C Aerobic Partial to complete inhibition on HE or XLD upon subculture

User Quality Control


CRITERION™ Tetrathionate Broth Base powder should appear homogeneous, free-flowing, and white in color. The prepared media should appear clear, with a precipitate, and milky white in color. Iodine-Iodide Solution (Cat. no. Z129) should appear dark amber to brown in color.


1. Anderson, N.L., et al. Cumitech 3B; Quality Systems in the Clinical Microbiology Laboratory, Coordinating ed., A.S. Weissfeld. American Society for Microbiology, Washington, D.C.

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

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

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

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

6. Quality Assurance for Commercially Prepared Microbiological Culture Media, M22. Clinical and Laboratory Standards Institute (CLSI - formerly NCCLS), Wayne, PA.

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

8. The United States Pharmacopeia, 21st rev. 1985. U.S. Pharmacopeial Convention, Rockville, MD.

9. Speck. 1984. Compendium of Methods for the Microbiological Examination of Foods, 2nd ed. APHA, Washington, D.C.

10. Greenberg, et al. 1992. Standard Methods for the Examination of Water and Wastewater, 18th ed. APHA, Washington, D.C.

11. U.S. Food and Drug Administration. Bacteriological Analytical Manual. AOAC, Arlington, VA.

12. Hajna, A.A., and Damon, S.R. 1956. New Enrichment and Plating Media for the Isolation of Salmonella andShigella Organisms. Applied Micro.; Vol. 4, No. 6:341-346.

13. Knox, R., Gell, P.G.H., and Pollock, M.R. 1942. Selective Media for Organisms of the Salmonella Group. J. Pathol. Bact.; 54:469-483.

14. Marshal, R.T. 1992. Pathogens in Milk and Milk Products, p. 152. Standard Methods for the Examination of Dairy Products, 16th ed. American Public Health Association, Washington, D.C.

15. Vanderzant, C., and Splittstoesser, D.F. 1992. Salmonella, p. 381. Compendium of Methods for the Microbiological Examination of Foods, 3rd ed. American Public Health Association, Washington, D.C.

16. Knox, R., Gell, G.H., and Pollock, M.R. 1943. The Selective Action of Tetrathionate in Bacteriological Media. J. Hyg. Camb.; 43:149-158.

17. Official Methods of Analysis, 15th ed. 1990. AOAC, Arlington, VA.

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