Survival kinetics of Ephestia kuehniella eggs during 46-75 °C heat treatment

The effect of heat treatment on the survival of Ephestia kuehniella eggs was examined. Samples of 60 eggs were immersed in hot water at constant temperature in the 46-75 _C range for 5-1200 s. Following heat treatment and cooling, the eggs were stored at 24 _ 1 _C in a growth chamber for 7 days before survival evaluation. Statistical analysis of the data demonstrated that the thermal survival kinetics were best represented by a first-order reaction. The rate constant had an Arrhenius-type dependence over the 54- 75 _C temperature range. Kinetic parameters were estimated by non-linear regression. The activation energy (Ea) and rate constant (kref) at the reference temperature (Tref¼ 64.8 _C), were determined as 102.2_ 6.2 kJ mol_1 and 0.061 _ 0.003 s_1, respectively, over the 54-75 _C temperature range. A 0.01% survival rate was obtained after 50 s at 75 _C. The data at temperatures below 50 _C were not in accordance with those at higher temperatures. Above this temperature, mortality was likely due to physiological disorders, as noted on a DSC thermogram.