M-Tergitol 7 Agar w/ Meat extract (Revised as M-Tergitol 7 Agar with HM Peptone)

M-Tergitol 7 Agar w/ HM Peptone is a selective and differential medium for recovery of injured coliforms from chlorinated water using membrane filtration technique. Tergitol-7 acts as surface-active agent which inhibit growth of gram-positive bacteria as well as swarming of Proteus. Lactose is the fermentable carbohydrate. Lactose fermentors produce yellow colonies due to reaction with bromothymol blue, the pH indicator present in the medium. TTC is reduced by lactose-negative bacteria such as Salmonella species produces dark red colonies. Lactose-positive Escherichia coli and coliform bacteria reduce TTC weakly, hence their colonies are yellow orange.