MacConkey (MAC) Agar is a selective and differential medium used for the detection and isolation of Gram-Negative enteric bacilli. Escherichia coli can ferment lactose to produce acid which results in a pH drop. This is indicated by neutral red resulting in pink colonies. Increased acid production results in the precipitation of bile salts, or a halo, around lactose fermenting bacteria. Non-lactose fermenting bacteria such as Salmonella spp. grow but remain colorless with no bile precipitate. • Product meets AOAC, BAM, CLSI, and Harmonized USP/EP/JP, NF, SM-Dairy, and SMWW reference methods and performance criteria.• MacConkey Agar should be used by trained professionals within a laboratory setting. • For in vitro diagnostic (IVD) use.• Product is not intended for use in the diagnosis or treatment of disease or other human conditions.