EVALUATION OF RECOVERY PROTOCOLS FOR HEAT-STRESSED ENTEROVIRULENT ESCHERICHIA-COLI

Four recovery protocols (25 and 37 degrees C, static and shaken) with tryptone soya broth were evaluated for their ability to allow recovery of a heat stressed (56 degrees C for 31 min) type strain, enteropatho genic, enterotoxigenic, enteroinvasive and enterohaemorrhagic Escheric hia coli. Using analysis of variance, no significant difference was fo und between static and shaken cultures. Using pooled data for both sta tic and shaken cultures and all five E. coli types, an incubation temp erature of 37 degrees C was found to be optimal for simple detection ( presence or absence) but an incubation temperature of 25 degrees C was found to be optimal if used before quantitative detection methods. In addition, a novel statistical method is described, which can be appli ed to other recovery protocols, to determine the efficacy of each. (C) 1996 Academic Press Limited