DMFit version 2.1
An Excel add-in for fitting sigmoid curves
DMFit is an Excel add-in (Excel 5 or above), fitting curves where a linear phase is preceded and followed by stationary phases. DMFit (DM: Dynamic Modelling) is based on Baranyi, J. & Roberts, T.A. (1994): A dynamic approach to predicting bacterial growth in food. Int. J. Food Microbiol. 23. 277-294.
The main difference between this model and other sigmoid curves like Gompertz, Logistic, etc. is, that the mid-phase is really very close to linear, unlike those classical sigmoid curves which have a pronounced curvature there.
A user-friendly stand-alone application, called MicroFit, programming the same model, is also available from this web-site. While Microfit fits and compares individual growth curves and their parameters based on F-test, DMfit fits and plots a set of curves.
DMFit is part of the system used in-house at the Institute of Food Research to model the time-variation of the logarithm of cell concentrations of bacterial batch cultures. It has been the main tool in the development of the models behind ComBase Predictor ( www.combase.cc).
Technincal warning: you need to allow macros to run when opening DMFit in Excel. It is known that there are some formatting problems with DMFit on non-English version of Excel. Some facilities do not work on Excel 2007.
If you have any general enquiries regarding this software please contact IFR via email: combase@bbsrc.ac.uk
