Lysine Iron Agar is used for the differentiation of microorganisms on the basis of lysine decarboxylase and hydrogen sulfide production. Lysine Iron Agar is not intended for use in the diagnosis of disease or other conditions in humans. Lysine Iron Agar is prepared according to the formulation of Edwards and Fife, who developed the medium to detect Salmonella arizonae. S. arizonae ferments lactose rapidly, and the authors found expected H2S production on Triple Sugar Iron Agar was suppressed. Detection of S. arizonae is important because it has been implicated in food borne infections. By eliminating lactose and incorporating lysine, Edwards and Fife devised a medium differentiating enteric bacilli based on their ability to decarboxylate or deaminate lysine and produce abundant hydrogen sulfide. This medium is recommended for detecting rapid lactose-fermenting S. arizonae.