Moeller Decarboxylase HiVeg™ Broth w/ Lysine HCl is used for differentiation of bacteria on the basis of their ability to decarboxylate L-Lysine hydrochloride. Ornithine is decarboxylated to form cadaverine Formation of the amine cadaverine increases the pH of the medium, changing the colour of the indicator from yellow to purple. Bromo cresol purple is the pH indicator. If the organisms do not produce the appropriate enzyme, the medium remains acidic, yellow in colour.Pseudomonas aeruginosa shows poistive Arginine decarboxylase activity, Salmonella and Shigella species shows delayed positive activity. This medium is prepared by replacing animal peptones with vegetable defined peptones to avoid BSE/TSE/GMO risk.