MacConkey Broth W/ Bromo Cresol Purple and NaCl

 Principle

• MacConkey broth purple is composed of peptone, lactose, sodium taurocholate, sodium chloride, and bromocresol purple. Peptone provides nitrogen and other nutrients necessary for the growth of microorganisms.
• Lactose is a carbon source and plays an important role in the selection of lactose-fermenting microbes. Sodium taurocholate is a selective agent, that inhibits the growth of gram-positive organisms.
• Bromocresol purple is a pH indicator dye. Sodium chloride maintains osmatic equilibrium.
• A lactose-fermenting organism shows prominent growth and produces acid and gas, causing the medium to turn yellow. Non-fermenting organisms produce good growth but will not produce acid or gas.

 Use: Recommended for presumptive identification of coliforms from clinical, dairy, and food samples.