Tryptophane Culture Broth, DEV, DEV, ISO 16654, for microbiology, 500 g, plastic

Escherichia transform lactose under acid production via β-galactosidase, and are negative in oxidase test and positive in indole production test. Kovac Reagent (Art. No. 2950.1) is added to 24-48 h old cultures in a concentration of 0.2 to 0.5 ml per 5 ml broth. A colour shift to dark red shows presence of indole.