Heating food in households or in industrial production processes by means of energy input from a high-frequency energy field such as microwaves is a widely used method.

Process intensification with microwaves

We are currently researching the further development of this technology to achieve continuous process control with rapid and, at the same time, homogeneous heating for the preservation or further processing of liquid and highly viscous products (e.g. milk concentrates or foods with chunky components).

The special expertise of Fraunhofer IGB in this field is the design of the reactors and the homogeneous waveguide coupling of the energy field. Basing our work on the analysis of the product-specific energy absorption, we are further developing models for applications of microwave reactors in the production of foodstuffs. We then investigate these models by carrying out scientific studies.

In addition to this, the high-frequency technology supports thermal extraction methods and increases the process efficiency, for example by minimizing the extraction time or the use of solvents.


  • Continuous system
  • Targeted energy input by means of specific antenna design
  • Shorter heating time
  • Improved sensory product characteristics
  • Reduced fouling


  • Microwave pasteurization of milk and viscous milk products (e.g. yoghurt)
  • Microwave pasteurization of fruit juice and juice concentrates
  • Heating or pretreatment of intermediate products

Reference projects


In the EU-funded project MicroMilk, the Fraunhofer IGB – together with the University of Hohenheim and other partners – have developed a novel method for pasteurization of milk with microwaves. The system preserves the valuable components of milk, reduces the use of cleaning agents and is also suitable for heating highly viscous and concentrated dairy products more quickly than previously. The core of the microwave method and a result of extensive simulation is a compact reactor, which is divided into different compartments. The microwaves are coupled into a waveguide, which simultaneously acts as the reaction chamber. In the follow-up project MicroMilk Demo the system now is being demonstrated in industry.

Integrated engineering approach validating reduced water and energy consumption in milk processing for wider food supply chain replication – EnReMilk


Fifteen European partners are working together on optimizing novel water-and energy-saving technologies and integrating them into selected dairy processing lines, while maintaining the quality and safety of the corresponding products.

Project duration: January 2014 – December 2017