ABSTRACT
Throughout the Vessel or Package .................................................... 145 5.5.8 Models Accounting for Package Shrinkage due to
Hydrostatic Compression .................................................................. 146 5.5.9 Heat Source: the Compression Heating Model ................................. 146 5.5.10 Materials and Their Properties in a Multicomponent Model ............ 146 5.5.11 Multiple Unit Operations in a Single Model ...................................... 147 5.5.12 Computational Demand and Solver Speed Required ........................ 147 5.5.13 Invested Time in Model Development ............................................... 148 5.5.14 Adaptability to System and Process Modifi cations ........................... 148
5.6 Concluding Remarks ..................................................................................... 148 5.6.1 Thermophysical Property Determination .......................................... 148 5.6.2 Analytical Modeling ......................................................................... 149 5.6.3 Numerical Modeling ......................................................................... 149 5.6.4 Macroscopic Models ......................................................................... 149 5.6.5 ANN .................................................................................................. 150 5.6.6 Model Validation with Temperature
and Microbial Measurements ............................................................ 150 Nomenclature ......................................................................................................... 151 References .............................................................................................................. 154
High-pressure high-temperature (HPHT) treatment, also known as pressure-assisted thermal processing (PATP), is an emerging preservation method for the development of shelf-stable low-acid food products. HPHT involves combining pressures of 600800 MPa with moderate initial chamber temperatures of 60°C-90°C, and takes advantage of the increasing process temperature during pressurization to eliminate spore-forming bacteria (Matser et al., 2004; Margosch, 2005). For instance, pressurization temperatures of 90°C-116°C combined with pressures of 500-700 MPa have been used to inactivate a number of strains of Clostridium botulinum spores (Farkas and Hoover, 2000; Margosch et al., 2004). Other researchers showed that certain bacterial endospores (C. sporogenes, Bacillus stearothermophilus, B. licheniformis, B. cereus, and B. subtilis) in selected matrices like phosphate buffer, beef, vegetable cream, and tomato puree (Gola et al., 1996; Raso et al., 1998; Rovere et al., 1998; Meyer et al., 2000; Balasubramanian and Balasubramaniam, 2003; Krebbers et al., 2003) can be eliminated after short-time exposure to temperatures and pressures above 100°C and 700 MPa, respectively.
