MacConkey Agar（Granular）

Testing principle:Gelatin Pancreatic Digest of Casein and Peptones provide carbon and nitrogen sources， vitamins， and growth factors；Bile Salts and Crystal Violet inhibit the growth of Gram-positive bacteria；Sodium Chloride maintains osmotic equilibrium; Agar serves as the solidifying agent of the medium；Lactose serves as a fermentable carbohydrate; Neutral Red acts as a pH indicator. When bacteria ferment lactose to produce acid， colonies appear pink with a turbid zone of bile salt precipitation surrounding them.