Lab M's modified Lauryl Sulphate Tryptose broth with MUG and Tryptophan (ISO) is designed specifically to enumerate presumptive E.coli from milk and milk products.
The broth uses the Most Probable Number (MPN) technique according to ISO 11866-1:2005.
ISO specifications indicate that this technique can be applied not only to milk, but also a wide range of liquid and dried milk products, cheese, butter, ice creams, custard, desserts and cream.
The key to E.coli enumeration is the addition of 4-methylumbelliferyl-B-D-glucuronide (MUG) to the standard Lauryl Tryptose broth formulation, allowing positive discrimination of E.coli strains.
The majority of E.coli produce the B-glucuronidase enzyme, resulting in hydrolysis of MUG and the release of a fluorogenic compound.
Tubes that fluoresce under UV light are confirmed for E.coli by a positive indole reaction when Kovac's reagent is added to the tube.
