Selective and enrichment media for the isolation and enumeration of ‘total’ Enterobacteriaceae, coliforms, faecal coliforms and E. coli from foods are described. The effects of time and temperature of incubation are discussed. Reports of some comparative studies of these media and factors to be considered in the selection of media for this group of organisms are noted and the difficulties associated with the isolation and enumeration of pathogenic serotypes of E. coli considered.