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Ultrasonic Sensor for the transmission of signals for process control for high pressure processing


Key words high pressure, packaging, treatment, automated processing, process control, food development
Latest version 2011/08/23
Completed by DIL

How does it work?

Primary objective Online temperature measurement under high pressure conditions.
Working principle To determine the temperature, a resistance based sensor is utilized during high pressure treatment to change the frequency of an ultrasonic emitter. Battery and electronics to operate the ultra-sonic device are encapsulated and are located (submarine-like) within the treatment chamber of the high pressure vessel. A microphone on the outside of the vessel records the frequencies transmitted by the device in the vessel. A computer program does the translation into a temperature signal. The sensor has an accuracy of ± 0.1°C in a range of 0 to 80°C and can be used in a pressure range between 0.1 to 600 MPa.

In addition p-T-pH diagrams and kinetic models of desired and undesired reactions are available. In addition to microbial inactivation the reaction rate of undesired reactions (changes in colour and texture, fat oxidation) were developed. Further on characterisations of pH – values under high pressure now can make use of optical in-situ techniques. For the detection of pH in different, homogenous components of meat products immobilised indicators on optical fibres were developed. Thus, modelling and numerical simulation are possible; time- and position-dependent temperature distribution and flow pattern as well as reaction kinetics of desired and undesired reactions now can be calculated. The purpose of the device is to transmit temperature changes during pressure generation. The sensor can be placed manually in, on, at different substance brought into the high-pressure vessel.
Real-time data can be transmitted wireless, allowing a reduction of safety margins and over-processing, a reduction of processing time, a higher treatment capacity and productivity as well as a reduction of energy consumption [1][2].

Additional effects
  • Automated process control for high pressure treatments
  • Product development for new products
  • Avoiding additives
Important process parameters -
Important product parameters -

What can it be used for?

Products high pressure vessels
Operations Measuring temperature and pressure.
Solutions for short comings
  • High quality preservation
  • New technology for food fabrication

What can it NOT be used for?

Products -
Operations -
Other limitations -
Risks or hazards Possibility of wrong measurement due to incorrect calibration and / or insufficient power supply.


Maturity Industrially available for high pressure vessels (industry machines).
Modularity /Implementation Expandable for additional sensors for example pressure, pH-sensors, color, etc.
Consumer aspects Easy to use.
Legal aspects
  • Machinery Directive 2006/42/EC
  • Regulation (EC) No 1935/2004 (materials in food contact)
Environmental aspects Optimizing production processes; energy saving.

Further Information

Institutes DIL, University of Erlangen-Nürnberg
Companies Hiperbaric, Uhde-HPT
  1. Toepfl, S., Mathys, A., Heinz, V. Knorr, D. (2006). Review: Potential of emerging technologies for energy efficient and environmentally friendly food processing. Food Reviews International, 22(4), 405-423.
  2. Heinz, V. (2000). Hochdruckpasteurisation von Fleischerzeugnissen - Stand der Technik und praktische Erfahrung. 24. Informationstagung 'Fleischtechnologie'; Technische Fachhochschule Berlin, Berlin.
  3. Stippl, V. (2005). Optical In-Situ Measurement of the pH-Value During High Pressure Treatment of Fluid Food. Dissertation, TU Munich.
  4. Alpas, H., Kalchayanand, N., Bozoglu, F. and Ray, B. (2000). Interactions of high hydrostatic pressure, pressurization temperature and pH on death and injury of pressure-resistant and pressure-sensitive strains of foodborne pathogens. International Journal of Food Microbiology 60, 33-42.
  5. Stewart, C.M., Jewett, F.F., Dunne, C.P. and Hoover, D.G. (1997) Effect of concurrent high hydrostatic pressure, acidity and heat on the injury and destruction of Listeria monocatogenes. Journal of Food Safety 17, 23-36.
  6. Rauh, C., Baars, A., Delgado, A. (2006). Analysis of Inhomogeneous Thermofluiddynamical Processes in Short Time High Pressure Treatment of Liquid Foods. In Proc. of the 4th Int. Conf. on High Pressure Biosci. and Biotechnol., Tsukuba, 25-29 September 2006, 186-191.
  7. Delgado, A., Rauh, C., Kowalczyk, W., Baars, A. (2008). Review of modelling and simulation of high pressure treatment of materials of biological origin. Trends in Food Science and Technology (online published).


  • EP 0689391 B1 (1996)
  • EP 0752211 B1 (2001)
  • EP 1100340 B1 (2001)
  • DE 3734025 C2 (1989)
  • EP 1112008 B1 (2001)
  • EP 1201252 B1 (2002)
  • EP 0683986 B1 (2001)
  • EP 0748592 B1 (2000)

- - Sensors and Indicators 2.1.1 physical other ICT Sciencedirect, Web of science Search terms: high pressure treatment, pH-value high pressure treatment WikiSysop :Template:Review document :Template:Review status

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Created by Claudia Siemer on 23 August 2011, at 14:21