Inactivation kinetics of Bacillus atrophaeus in liquid hydrogen peroxide for aseptic package sterilization

Abstract

Liquid hydrogen peroxide is used as a common sterilant for the aseptic packaging materials. Based on the Food Safety Objective (FSO) for specific products, a surrogate organism, Bacillus atrophaeus, is used to validate the sterilization processes. This study aims to develop a methodology for the kinetic inactivation parameter estimation of B. atrophaeus. Spores of B. atrophaeus were challenged with various peroxide concentrations (20%, 28%, and 33%; v/v) and temperatures such as 23, 55, 71.1, and 82.2 °C. The log-linear and Weibull models were used for the inactivation models for liquid peroxide at different temperatures. The parameters were estimated at a reference temperature of 80 °C for log-linear and Weibull models. With peroxide concentrations of 20, 28, and 33%, the log-linear model estimated D values were 0.95, 0.47, and 0.08 min and z values were 94.67, 86.86, and 41 °C, respectively. The Weibull model δ values were 0.31, 0.23, and 0.05 min with a z value of 85.18, 81.23, and 41.39 °C for 20, 28, and 33% peroxide, respectively. The RMSE values varied from 0.60 to 0.79 log CFU/ml, the sum of the squares was between 27.3 and 39.7, and the parameters' relative errors were less than 6%.