A medium recommended by the Harmonised European Pharmacopoeia for the selective enrichment of Escherichia coli from non-sterile pharmaceutical samples.
Conforms to USP/EP/JP performance specification. Gelatin peptone provides a source of nitrogen, while lactose is a fermentable carbohydrate. Ox bile acts a selective agent inhibiting most Gram-positive organisms and bromocresol purple acts as a pH indicator. A colour change from purple to yellow indicates growth of a bile tolerant, lactose fermenting organism such as Escherichia coli. According to the Harmonised European Pharmacopoeia, MacConkey Broth is used as a selective enrichment broth, with subculture performed onto MacConkey Agar.