Tests for E.coli and other coliforms in water. Coliscan media has a patented combination of color producing chemicals and nutrients that indicate coliforms and E.coli by producing different colorsmaking identification and isolation easy. When testing a water sample it is added to the medium, which is poured into the prepared petri-dishes and incubated for 24-48 hours. E.coli will produce purple-blue colonies, while the coliform bacteria will grow as pink-magenta colonies. 50 tests/kit.