grow_baranyi: The Baranyi and Roberts Growth Model
Description
The growth model of Baranyi and Roberts (1995) written as analytical solution
of the system of differential equations.
Usage
grow_baranyi(time, parms)
Value
vector of dependent variable (y).
Arguments
time
vector of time steps (independent variable).
parms
named parameter vector of the Baranyi growth model with:
y0 initial value of abundance,
mumax maximum growth rate (1/time),
K carrying capacity (max. abundance),
h0 parameter specifying the initial physiological state of
organisms (e.g. cells) and in consequence the lag phase
(h0 = max growth rate * lag phase).
Details
The version of the equation used in this package has the following form:
$$A = time + 1/mumax * log(exp(-mumax * time) + exp(-h0) - exp(-mumax * time - h0))$$
$$log(y) = log(y0) + mumax * A - log(1 + (exp(mumax * A) - 1) / exp(log(K) - log(y0)))$$
References
Baranyi, J. and Roberts, T. A. (1994).
A dynamic approach to predicting bacterial growth in food.
International Journal of Food Microbiology, 23, 277-294.
Baranyi, J. and Roberts, T.A. (1995). Mathematics of predictive microbiology.
International Journal of Food Microbiology, 26, 199-218.
time <- seq(0, 30, length=200)
y <- grow_baranyi(time, c(y0=0.01, mumax=.5, K=0.1, h0=5))[,"y"]
plot(time, y, type="l")
plot(time, y, type="l", log="y")