Cat. no. C6840 CRITERION™ Salmonella Shigella (SS) Agar 120gm
Cat. no. C6841 CRITERION™ Salmonella Shigella (SS) Agar 500gm
Cat. no. C6842 CRITERION™ Salmonella Shigella (SS) Agar 2kg
Cat. no. C6843 CRITERION™ Salmonella Shigella (SS) Agar 10kg
Cat. no. C6844 CRITERION™ Salmonella Shigella (SS) Agar 50kg


Hardy Diagnostics CRITERION™ Salmonella Shigella (SS) Agar is a highly selective agar used for the isolation of Salmonella and some Shigella.

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.


Salmonella Shigella (SS) Agar is a selective differential agar medium used for isolation of pathogenic Enterobacteriaceae, specifically Salmonella spp. and Shigella spp. from foods, other sanitary materials and clinical specimens. Early studies indicated that SS Agar was superior to other media in the isolation of Salmonella and Shigella from specimens.(1-3) Later investigators determined that SS agar was inferior to Hektoen Enteric (HE) Agar and XLD Agar in the recovery ofShigella.(4-7) Inhibitory action on coliforms and gram-positive bacteria is obtained by the bile salts mixture and brilliant green in the medium. Sodium citrate inhibits gram-positive bacteria. Neutral red is a pH indicator and those bacteria which ferment lactose produce pink colonies. Some Salmonella and Proteus spp. produce black-centered (precipitated ferrous sulfate) colonies as a result of H2 S production.


Gram weight per liter: 60.0gm/L
Lactose 10.0gm
Bile Salts Mixture 8.5gm
Sodium Citrate 8.5gm
Sodium Thiosulfate 8.5gm
Beef Extract 5.0gm
Pancreatic Digest of Casein 2.5gm
Peptic Digest of Animal Tissue 2.5gm
Ferric Citrate 1.0gm
Brilliant Green 0.3mg
Neutral Red 25.0mg
Agar 3.5gm

Final pH 7.0 +/- 0.2 at 25ºC.

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


Store the sealed bottle containing 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 pinkish-beige.

Store the prepared culture media at 2-8ºC.



1. Suspend 60.0gm of the dehydrated culture media in 1 liter of distilled or deionized water.

2. Heat to boiling and mix to dissolve completely. Do not autoclave.

3. Cool to 45-50ºC.

4. Dispense into sterile containers as desired.


Specimen Collection: Consult listed references for information on specimen collection.(1,2,5) Infectious material should be submitted directly to the laboratory without delay and protected from excessive heat and cold. If there is to be a delay in processing, the specimen should be inoculated onto an appropriate transport media and refrigerated until inoculation.

Method of Use: Plates should be warmed to room temperature and agar surface should be dry prior to inoculating. Inoculate and streak the specimen as soon as possible after collection. 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. Incubate plates aerobically at 35-37ºC. for 18-24 hours (some organisms may take longer than 24 hours for visible growth to appear). Examine colonial morphology.


For information on procedures and interpretation of results, consult listed references or refer to the prepared media Instructions for Use (IFU) for Cat. No. G50.


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


Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Salmonella enterica
ATCC ® 14028
A 18-24hr 35°C Aerobic Good growth; colorless colonies with black center
Shigella flexneri
ATCC ® 12022
A 18-24hr 35°C Aerobic Good growth; colorless colonies
Escherichia coli
ATCC ® 25922
B 18-24hr 35°C Aerobic Partial to complete inhibition; red colonies

User Quality Control


CRITERION™ Salmonella Shigella (SS) Agar powder should appear homogeneous, free-flowing, and light pinkish-beige in color. The prepared media should appear clear to trace hazy, and reddish-orange 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. American Public Health Association. Standard Methods for the Examination of Water and Wastewater, APHA, Washington, D.C.

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

6. Pub Health Ref.; 57:521, 1942.

7. J. Lab. Clin. Med.; 1081, 1942.

8. Am. J. Pub. Health; 31:363, 1941.

9. Am. J. Clin. Path.; 35:476, 1965.

10. Appl. Micro.; 15:656, 1969.

11. Appl. Micro.; 21:32, 1971.

12. Appl. Micro.

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