Phenyl Alanine Agar Slant

This slant is recommended for differentiation of Proteus & Providencia group of organisms from other members of Enterobacteriaceae on the basis of their ability to form phenyl pyruvic acid from phenylalanine. Phenylalanine Agar differentiates Proteus and Providencia group from other members of Enterobacteriaceae. After incubation add 0.2 ml of 10% ferric chloride solution. A light to deep green color indicates positive reaction and no color change indicates negative reaction. Interpret the results within 5 minutes upon addition of reagent as the green colour fades quickly