Glutamate broth is used enumeration of β-glucuronidase positive E.coli in food products by the MPN technique. It is recommended when the microorganisms are found in a sub-optimal state due to exposition to stress including freezing, desiccation, disinfection or high salinity. The described method does not allow the detection of strains of Escherichia coli that do not develop at 44°C, and, in particular, those that are β-glucuronidase negative, as the case of E. coli O157 and a few other strains of pathogenic E. coli.