Tergitol-7 Agar Base

Tergitol-7 Agar Base is recommended for selective enumeration and identification of coliform organisms. Addition of Triphenyl Tetrazolium Chloride (TTC) Solution (FD057) makes media selective. Sodium heptadecyl sulphate (Tergitol-7) inhibits gram-positive bacteria and restricts swarming of Proteus . Lactose is fermentable carbohydrate source. Bromo thymol blue is the pH indicator. Proteose peptone and yeast extract serve as sources of carbon, nitrogen and other essential nutrients including vitamin B complex. TTC is reduced by the bacterial cell except Escherichia coli and Klebsiella aerogenes to form formazan, a red coloured insoluble complex, thereby producing red coloured colonies.The yellow colonies with deep yellow halo after incubation at 44°C is identified as faecal coliform bacteria. E.coli appears as yellow with red centre on this medium.