Modeling the inactivation kinetics of bacillus spores by glutaraldehyde

Aims: Our goal was to develop a mathematical kinetic model to predict the sporicidal activity of glutaraldehyde, which is an active ingredient frequently used in commercial products employed for liquid disinfection and decontamination. Methods and Results: We used our previously published data on spore inactivation by glutaraldehyde to develop a predictive model obtained by calculating multiple independent modifying functions. The model was then validated by comparing model predicted values to new experimental data. For model validation, quality‐controlled spores of Bacillus athrophaeus (previously and generally known as Bacillus subtilis globigii) were exposed under conditions where several physicochemical variables were modified simultaneously, and the spore surviving fractions were measured by titration. Conclusions: The model predicted within one order of magnitude variations in sporicidal effectiveness due to changes in main parameters (glutaraldehyde concentration, temperature or time‐duration of the treatment). Other parameters such pH, salinity and the effect of serum concentration were also addressed, albeit with less accuracy. Significance and Impact of the study: The model should be useful to quantitatively estimate the effectiveness of glutaraldehyde‐based disinfectants, decontaminants, and germicides under the described conditions, particularly when limited data are available or when spore virulence (like that of Bacillus anthracis) precludes extensive experimentation. A similar approach could predict the effectiveness of a variety of decontaminant and disinfecting agents.