Modified Tergitol 7 Agar Base (Tergitol -7 Agar Base, Modified)

Modified Tergitol 7 Agar Base (Tergitol -7 Agar Base, Modified) is recommended for selective isolation and enumeration of coliform organisms in water by membrane filtration method. The composition and performance criteria are in accordance with ISO 9308-1:2014. Triphenyl Tetrazolium Chloride (TTC) Solution and Sodium heptadecyl sulphate (Tergitol-7) are selective agents. 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.