Surface sterilisation of food packaging

Lead University: University of Birmingham

Professor Peter Fryer, Professor Serafim Bakalis, Professor Mark Simmons, Dr Flora Challou, =Dr Estefania Lopez-Quiroga, Suwijak Hansriwijit, Alexander Kitt, Andrew Wainwright


Campden BRI



Thermal processing is the most common technique employed for surface decontamination of food packages. To achieve the inactivation of the targeted microorganisms, a top-up pasteurisation treatment can be used. Industrially, the process is carried out in water spray tunnels where the packages are heated for 5-10 minutes at 95°C as standard. Too low water flow per pack would give slow heating to the process, which could lead to biological risks, whilst a too high water flow would result into pumping and heat losses that would be excessive for a profitable operation. Therefore, there exists a scope for saving energy, water and increasing operation efficiency through the optimisation of the standard operation.

Aims and objectives

To model and simulate TTIs operation, to optimise thermal process and to minimise energy, waste and environmental impacts.

  • to study temperature transients and pasteurisation process in inversion conditions.
  • to study energy efficiency of falling film pasteurisers.


  • monitorisation of the system’s thermal response for different formulations (rheology) and processing conditions (e.g. inversion time, spray film temperature and flow rate) using TTI’s and /or thermocouples
  • calculation of corresponding heat transfer coefficients
  • development of mathematical models that describe heat transfer dynamics during pasteurisation by inversion and with spray shower


  • Inversion works: P-values increased by 40%-90% depending on process conditions.
  • Combinations of inversion times - filling temperatures provided that ensure safety.
  • Models developed and validated for both inversion and spray pasteurisation.
  • Optimal mass flow found as function of cost and process time for the spray process.

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