Himedia Phenol Red Sucrose Broth

Phenol Red Sucrose Broth is recommended for studying sucrose fermentation by the pure cultures of microorganisms. Positive reaction is indicated by the change in colour of medium to yellow due to acid production as indicated by phenol red, a pH indicator in the medium. Gas production is indicated by the bubbles formation and entrapped in Durhams tube. Citrobacter freundii, Enterobacter aerogenes, Klebsiella pneumoniae, Proteus vulgaris and Serratia marcescens are known sucrose fermentors and gives positive reaction. Escherichia coli, Salmonella Typhi, Salmonella Typhimurium and Shigella flexneri do not ferment sucrose, hence there is no colour change of the medium.