Phenol Red Dulcitol Broth is recommended for dulcitol fermentation studies 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. Salmonella Typhimurium is a known dulcitol fermentors and gives positive reaction. Other Enterobacteriaceae; Citrobacter freundii, Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Salmonella Typhi, Shigella flexneri and Serratia marcescens do not ferment dulcitol, hence there is no colour change of the medium.