AimsTo explore the predictions of a novel rearrangement of the Baranyi-Roberts model (BRM) with time to detection data obtained from optical density data of microbial growth. Methods and ResultsGrowth of Escherichia coli and Salmonella Typhimurium under mild conditions of temperature (25-37 degrees C), salt (0086, 051 and 103moll(-1)) and pH (685-45) was examined using optical density. Time to detection (TTD) data were fitted to a model based on a rearrangement of the BRM. Observations showed compatibility with standard viable count studies and produced highly accurate specific growth rates and lag phase durations. At high salt and low pH, however, there was a substantial dependency on the initial inoculum for the observation of visible growth. At 30 and 37 degrees C, with 103moll(-1) salt, and at pH <575, no visible growth was recorded for E.coli at initial inoculum levels below 10(7)CFUml(-1). ConclusionsThe rearranged BRM can be used directly with TTD data obtained from optical density measurements. Significance and Impact of the StudyA distinct advantage of the rearranged model is that it allows for a very simple interpretation of easily obtainable data using standard nonlinear regression. The rearranged model gives to TTD data the same modelling capability that the BRM gives to plate count data.