For fast detection and enumeration of Escherichia coli in foods using direct plating method. Dissolve 36.50gms in 1000ml of distilled water. Gently heat to boiling with gentle swirling and dissolve the medium completely. Sterilize by autoclaving at 15 psi (121°C) for 15 minutes. Cool to 500C and dispense them into sterile Petri plates. Appearance: Straw colour , pH (at 250C): 7.2 ± 0.2
TRYPTONE BILE AGAR for fast detection and enumeration of Escherichia coli in foods using direct plating method. Medium first introduced by Delaney, McCarthy and Grasso in 1962 as a method for detecting faecal coliforms in water supplies based on the production of indole on a bile medium at 44°C. The inoculum is placed onto the membrane on a resuscitation agar and incubated at 37°C for 4 hours. The membrane is then transferred to a Tryptone Bile Agar plate and incubated at 44°C: after incubation the membrane is flooded with indole reagent. Indole positive colonies produce a red colour on the membrane and are easily counted.