A computational model for temperature and sterility distributions in a pilot-scale high-pressure high-temperature process

Authors

  • Kai Knoerzer,

    Corresponding author
    1. Innovative Foods Centre, Food Science Australia, Private Bag 16, Werribee, VIC, Australia Food Futures Flagship, CSIRO, North Ryde, NSW, Australia
    • Innovative Foods Centre, Food Science Australia, Private Bag 16, Werribee, VIC, Australia Food Futures Flagship, CSIRO, North Ryde, NSW, Australia
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  • Pablo Juliano,

    1. Innovative Foods Centre, Food Science Australia, Private Bag 16, Werribee, VIC, Australia Food Futures Flagship, CSIRO, North Ryde, NSW, Australia
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  • Simon Gladman,

    1. Innovative Foods Centre, Food Science Australia, Private Bag 16, Werribee, VIC, Australia
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  • Cornelis Versteeg,

    1. Innovative Foods Centre, Food Science Australia, Private Bag 16, Werribee, VIC, Australia Food Futures Flagship, CSIRO, North Ryde, NSW, Australia
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  • Peter J. Fryer

    1. Centre for Formulation Engineering, Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
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Abstract

High pressure high temperature processing is a candidate food sterilization process in which heat is generated volumetrically within the food as a result of rapid pressurization to 600 MPa or higher. For commercial viability the temperature profile in the process should be as uniform as possible. A model has been developed to predict the flow and temperature fields inside a pilot scale (35 L) vessel during the pressure heating, holding and cooling stages of the process. Simulations on the empty vessel show that thermal conduction causes excessive cooling. The model agrees well with experimental results in which thermocouples are used to measure temperature throughout a metallic composite carrier inserted into the vessel. The model is used to design a Polytetrafluoroethylene (PTFE) carrier which produces thermal uniformity within the carrier. Predicted variations of sterility resulting from a process are produced using the F0-value distribution. No significant reduction of spores was seen in the empty vessel, while more than 94.6% of the PTFE carrier volume achieved a reduction greater than 1012. © 2007 American Institute of Chemical Engineers AIChE J, 2007

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