Tergitol-7 Agar Plate is supplied by HiMedia. It contains 25ml of sterile ready prepared media in 90 mm disposable plates. Tergitol-7 Agar Plate is used for the selective enumeration and identification of coliform organisms. It is advisable to store this product below 30C. Composition (in gm/L) is as follows:

Proteose peptone (5.00)

Yeast extract (3.00)

Lactose (10.00)

Sodium heptadecyl sulphate (Tergitol 7) (0.10)

Bromo thymol blue (0.025)

Agar (15.00)

Tergitol-7 Agar was originally designed by Chapman and later modified by incorporating 2,3,5-Triphenyl Tetrazolium Chloride (TTC) into the medium. Tergitol-7 Agar is a selective and differential medium used for the detection and enumeration of coliform organisms. Pollard reported the selective bactericidal property of sodium heptadecyl sulphate (Tergitol-7). Kulp et al documented the use of Tergitol-7 Agar with TTC in routine analysis of water and Mossel had used this medium for the examination of food materials. Proteose peptone and yeast extract present in the medium, serve as sources of carbon, nitrogen and other essential nutrients along with vitamin B complex. Sodium heptadecyl sulphate (Tergitol-7) inhibits gram-positive bacteria, Proteus swarming and ensures better recovery of coliforms. Bromo thymol blue is the pH indicator. Lactose fermenting organisms form yellow colonies with yellow zones while Klebsiella and Enterobacter form greenish yellow colonies. Lactose non-fermenters produce blue colonies. TTC is reduced by the bacterial cell, (except in case of Escherichia coli and Enterobacter aerogenes) to form formazan, a red coloured insoluble complex, which produces red coloured colonies.