Purple Broth Base

Purple Broth Base is recommended for the preparation of carbohydrate media used in fermentation studies for the cultural identification of pure cultures of enteric and other microorganisms. Positive reaction is indicated by change in colour of medium to yellow due to fermentation of carbohydrate and bromocresol purple the pH indicator in the medium. Gas produced is entrapped in Durham's tube. If the carbohydrate is not utilized or fermented, the color of the medium remainsunchanged or becomes more alkaline (darker purple) due to decarboxylation of the amino acids present in the medium.