Lauryl Tryptose Mannitol Broth with Tryptophan, 2.5 kg

Identification of bacteria that constitute the coliform group sometimes is necessary to determine the nature of pollution. It is of particular importance in reference to distinguishing the presence of Escherichia coli , an indicator of fecal contamination. Lauryl Tryptose Mannitol Broth w/ Tryptophan is a single tube medium used for the confirmation of E. coli in drinking water as recommended by report 71 (1). This medium is also recommended by the ISO committee (2) and is also a suitable medium as per the requirements of the EC Directive (3) 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 . Tryptose is the source of carbon, nitrogen, vitamins, amino acids and other essential growth requirements. Mannitol is the fermentable carbohydrate. Phosphates buffer the medium whereas sodium lauryl sulphate serves to inhibit accompanying noncoliform bacteria. L-tryptophan is a substrate of tryptophan deaminase enzyme. E. coli is confirmed by gas and indole production when incubated at 44°C for 24 hours. If the indole test is negative even if in a single tube medium, repeat the test in Tryptone Water (M463). Each tube showing acid and gas in the multiple tube test is subcultured to a tube of Lauryl Tryptose Mannitol Broth with Tryptophan and incubated at 44°C. Storage and Shelf-life: Store below 30°C in tightly closed container and the prepared medium at 2 - 8°C. Use before expiry date on the label. Reference: 1.Conant N.F 1950, Diagnostic Procedures and Reagents 3rd ed. APHA Inc. New York.