does salmonella ferment lactose
Non-Lactose fermenting bacteria such as Salmonella, Proteus species, Yersinia, Pseudomonas aeruginosa and Shigella cannot utilize lactose, and will use peptone instead. This forms ammonia, which raises the pH of the agar, and leads to the formation of white/colorless colonies on the petri plate.t contains bile salts (to inhibit most Gram-positive bacteria), crystal violet dye (which also inhibits certain Gram-positive bacteria), neutral red dye (which turns pink if the microbes are fermenting lactose). Composition: 1  Peptone - 17 g. 2  Proteose peptone - 3 g.