Product number: 7187

Tergitol 7 Agar is used for the selective isolation of coliform bacteria in a laboratory setting. Tergitol 7 Agar is not intended for use in the diagnosis of disease or other conditions in humans.

Tergitol 7 Agar, prepared according to the formula published by Chapman, is selective for Escherichia coli and members of the coliform group. Chapman reported that the addition of Tergitol 7 to a medium consisting of polypeptone and yeast extract permitted unrestricted development of all coliform bacteria, and inhibited Gram-negative spore-formers and Gram-positive organisms. Coliform counts on Tergitol 7 Agar were 30% higher than on other selective media.

Chapman modified his original Tergitol 7 Agar by adding 40 mg of triphenyltetrazolium chloride (TTC) per liter. This medium was helpful in the early recognition and identification of Escherichia coli. Confirmation of the presence of E. coli was possible after only 10 hours incubation at 35°C. Chapman also reported that Tergitol 7 Agar with added TTC gave a selective medium suitable for the isolation of Candida spp. and other fungi. Tergitol 7 Agar with TTC is useful for routine water analysis and the examination of foods.


Formula Liter
Enzymatic Digest of Casein 2.5 g
Enzymatic Digest of Animal Tissue 2.5 g
Yeast Extract 3 g
Lactose 10 g
Tergitol 7 0.1 g
Bromthymol Blue 0.025 g
Agar 15 g

Final pH: 6.9 ± 0.2 at 25°C
Formula may be adjusted and/or supplemented as required to meet performance specifications.


  1. Suspend 33 g of the medium in one liter of purified water.
  2. Heat with frequent agitation and boil for one minute to completely dissolve the medium.
  3. Autoclave at 121°C for 15 minutes.

OPTIONAL: Cool Tergitol 7 Agar to 50°C. Add 4 mL of either TTC Solution 1% or a filter sterilized 1% solution of TTC.

Order Details

Product # Product Description
7187T Tergitol 7 Agar, 5 kg

Reference Material

7187 - Tergitol 7 Agar, Product Information Sheet [English] [Portuguese]

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