TABLE 3.

Model parameters for heat-induced DPA release by B. subtilis 168 spores

ParameteraValueEquationFigure
D 98 (min)1831A
m 98 (min)4.261A
Δ98 (min)7.974B
Z (°C)6.331A
Zm (°C)18.564B
Z Δ (°C)14.674B
N 0 1.3 × 10611A
Nr 1311A
F 1 (AU)5084A
F 298 (AU)45084A
F 2105 (AU)48084A
F 2111 (AU)55084A
A 1 (%)894C
A 2 (%)8494C
  • a The parameters are defined as follows: D98, the D value at 98°C; m98, the DPA release delay parameter at 98°C (min); Δ98, the DPA release duration parameter at 98°C (expressed in minutes); Z, the temperature change that is required to change the D value by a factor of 10 (expressed in degrees Celsius); Zm, the temperature change that is required to change the m value by a factor of 10 (expressed in degrees Celsius); ZΔ, the temperature change that is required to change the Δ value by a factor of 10 (expressed in degrees Celsius); N0, the number of viable spores at time zero minus the rest population Nr; Nr, the heat-resistant rest population of the spores; F1, the minimum DPA concentration as measured by the emission of the Tb(DPA)+ complex (expressed in relative fluorescence or arbitrary units [AU]); F2, the maximum DPA concentration (arbitrary units) with the temperature (in degrees Celsius) in subscript; A1, the minimum DPA release (expressed as a percentage); A2, the maximum DPA release (expressed as a percentage).