Himedia Phenol Red Lactose Agar

Phenol Red Lactose Agar is used for studying lactose fermentation by the pure cultures of microorganisms. Positive reaction is indicated by the production of a yellow colour in agar due to acid production. Gas production is indicated by the splitting of agar or by the bubbles formation. Escherichia coli, Klebsiella pneumoniae are known lactose fermentors and gives positive reaction. Salmonella, Shigella species do not ferment lactose, hence there is no colour change of the medium.