# Lag Time in Microbial Growth

Lag Time in Microbial Growth

Frequently, when a microbial population is transferred into a new habitat, noticeable cell division only commences after what is known as a "lag time". According to the food microbiology literature, this lag time can be determined by extrapolating the tangent to the growth curve at its inflection point to the line , where is the inoculum's original size. In this Demonstration, simulated growth ratio data, with or without random scatter, is fitted to the Gompertz or stretched exponential (Weibullian) models using nonlinear regression. The tangent method is then used to calculate the lag time with the fitted parameters. It is shown that the lag time so calculated can depend on the growth model chosen and be substantially longer than that marking the time where growth can first be observed.

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