Derivation of a rigorous equation for the calculation of the F-value in isothermal sterilization processes.
The use of simplified equations utilizing the Z- and F-values to calculate the level of sterilization achieved in isothermal processes is very common in industry. This method assumes that the Z-value is independent of temperature. This is a simplifying assumption that is not based on a physically realistic microbial inactivation model. In the present work the appropriate equations for the Z- and F-values were derived with kinetic theory and utilized to predict the level of sterility obtained during isothermal sterilization. The F-value obtained with the proposed equation was always higher than the F-value obtained when the simplifying assumption was made. Therefore, the use of the equation proposed here for the F-value results in more realistic and generous estimates of the lethal effect on microorganisms produced by isothermal sterilization processes. Tables of the F-values so obtained are provided.
Armenante
P M
PM
New Jersey Institute of Technology, Department of Chemical Engineering, Chemistry, and Environmental Science, Newark 07102-1982.
D001709:Biotechnology / Q000379:methods*; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D007700:Kinetics; D008432:Mathematical Computing; D013242:Sterilization / Q000379:methods*; D013696:Temperature