MacConkey broth is composed of peptone, protease peptone, lactose, bile salt, sodium chloride, and neutral red. Peptone and protease peptone provide nitrogen and other nutrients necessary for the growth of microorganisms.
Lactose is a carbon source and plays an important role in the selection of lactose-fermenting microbes. Bile salt is a selective agent, that inhibits the growth of gram-positive organisms.
Neutral red is a pH indicator dye. When lactose is fermented, acid turns medium pink to yellow.
Use: Recommended for the enrichment and enumeration of lactose fermenting coliforms from pharmaceutical, clinical, and non-clinical samples, dairy, food, and water samples.
