Tag: <span>heat inactivation</span>

Heat inactivation is dependent both on temperature and time at temperature, making inter-assay and intervirus comparisons of heat sensitivity of viruses problematic. Historically, heat inactivation data for pathogens, including viruses, have been evaluated by determining decimal reduction value ([D] the time required to inactivate 1 log10 of the organism at a given temperature) and the incremental temperature required to decrease the D by 1 log10 (z). We recommend the use of a straightforward approach for extrapolating heat inactivation (i.e., inactivation vs. time at fixed temperature) data from measured to non-measured temperatures that is based not on the z value, but on a power function fit of the D vs. temperature plots. There needs to have been at least three temperatures evaluated in the inactivation vs. time kinetics studies in order to conduct these modeling analyses. For inter-assay and inter-virus comparisons of heat inactivation sensitivity, we propose the use of two modeled parameters: (1) temperature required to inactivate 1 log10 of virus in 0.5 minutes; and (2) time required for 1 log10 reduction in infectivity at 80°C. By using both modeled parameters, we have calculated consensus heat inactivation values for two caliciviruses (feline calicivirus and murine norovirus)…