Lauryl Tryptose Mannitol Broth w/ Tryptophan is used for confirmation of Escherichia coli in drinking water as recommended by report 71. This medium is also recommended by the ISO committee and is also a suitable medium as per the requirements of the EC Directive for the quality of drinking water. This medium may be used in parallel to Lauryl Tryptose Broth (M080) to detect non-lactose fermenting strains of E. coli.