Lab M has launched a modified Lauryl Sulphate Tryptose broth with MUG and tryptophan (ISO) for the presumptive enumeration of Escherichia coli from milk and milk products.
This is achieved using the Most Probable Number (MPN) technique according to ISO 11866-1:2005.
The key to E.coli enumeration is the addition of 4-methylumbelliferyl-B-D-glucuronide (MUG) to the standard Lauryl Tryptose broth.
Used in conjunction with the MPN technique, it allows presumptive E.coli to be enumerated from presumptive coliforms.
The addition of MUG allows the positive discrimination of E.coli strains.
The majority of E.coli produce B-glucuronidase enzyme, which enables them to hydrolyse MUG, resulting in the release of a fluorogenic compound.
Tubes which fluoresce under UV light are confirmed for E.coli by a positive indole reaction when Kovac's reagent is added to the tube.
