Reconciliation of the D/z model and the Arrhenius model: The effect of temperature on inactivation rates of chemical compounds and microorganisms.


Eastern Regional Research Center, USDA Agricultural Research Service, 600 E. Mermaid Lane, Wyndmoor, PA 19038, United States. Electronic address: [Email]


The effect of temperature on thermal inactivation of microorganisms and thermal degradation of certain chemical compounds can be either described by the Arrhenius model for the rate constant (k) or by the D/z model for the decimal reduction time (D). Although equivalent, it is difficult to directly reconcile these two models which have different model structures. This study hypothesized that the two models can be reconciled by linearization of the inverse of absolute temperature (1/T) and heating temperature (T), and the activation energy (Ea) can be directly calculated from z and their relationship is independent of T. The hypothesis was validated using the z and Ea of various chemical compounds, enzymes, and vegetative cells and spores of microorganisms in various substrates published in the literature. The results of this study show that the empirical models are practically reconciled.


Arrhenius model,D/z model,Kinetic analysis,Thermal inactivation,

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