title: Extended study on the influence of z-value(s) of single and multicomponent time-temperature integrators on the accuracy of quantitative thermal process assessment.
abstract: The possibilities and limitations of single- and multicomponent time-temperature integrators (TTIs) for evaluating the impact of thermal processes on a target food attribute with a Ztarget value different from the zTTI value(s) of the TTI is far from sufficiently documented. In this study, several thousand time-temperature profiles were generated by heat transfer simulations based on a wide range of product and process thermal parameters and considering a Ztarget value of 10 degrees C and a reference temperature of 121.1 degrees C, both currently used to assess the safety of food sterilization processes. These simulations included 15 different Ztarget=10 degrees CF121.1 degrees C values in the range 3 to 60 min. The integration of the time-temperature profiles with ZTTI values of 5.5 to 20.5 degrees C in steps of 1 degrees C allowed generation of a large database containing for each combination of product and process parameters the correction factor to apply to the process value FmultiTTI, which was derived from a single- or multicomponent TTI, to obtain the target process value 10 degrees CF121.1 degrees C. The table and the graph results clearly demonstrated that multicomponent TTIs with z-values close to 10 degrees C can be used as an extremely efficient approach when a single-component TTI with a z-value of 10 degrees C is not available. In particular, a two-component TTI with z1 and z2 values respectively above and below the Ztarget value (10 degrees C in this study) would be the best option for the development of a TTI to assess the safety of sterilized foods. Whatever process and product parameters are used, such a TTI allows proper evaluation of the process value 10 degrees CF121.1 degrees C.
authors.affiliation: Laboratory of Food Technology, Department of Food and Microbial Technology, Faculty of Agricultural and Applied Biological Sciences, Katholieke Universiteit te Leuven, Heverlee, Belgium. yann.guiavarch@agr.kuleuven.ac.be
authors.forename: Yann P
authors.initials: YP
authors.lastname: Guiavarc'h
authors.forename: Ann M
authors.initials: AM
authors.lastname: van Loey
authors.forename: Marc E
authors.initials: ME
authors.lastname: Hendrickx
mesh_terms: D001419:Bacteria / Q000254:growth & development*; D003198:Computer Simulation; D003257:Consumer Product Safety; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D006358:Hot Temperature; D008954:Models, Biological; D011786:Quality Control; D013242:Sterilization / Q000379:methods*; D013997:Time Factors