2012|13 Annual Report Fraunhofer IGB

70 DEVELOPMENT AND VALIDATION OF A NOVEL SYSTEM FOR MILK PASTEURIZATION Dr. rer. nat. Ana Lucía Vásquez-Caicedo, Ali Imran Javaid M.Sc., Dipl.-Ing. (FH) Alexander Lohner, Sildarista Fukohani-Lohner M.Sc. Initial situation The preservation of milk products requires microorganisms contained in the milk to be completely or partially eliminated by increasing the product temperature. Different processes such as pasteurization, thermization or sterilization (UHT) are differentiated according to their temperature/time proﬁles. The most common technique for applying heat is indirect heating using plate heat exchangers. This has the disadvan- tage that, due to the temperature gradient between the ex- changer surface and the product, deposits can form on the surfaces of the heat exchanger (fouling). The heat exchangers must therefore be regularly cleaned, leading to considerable costs due to downtimes and the use of energy and cleaning agents. It is therefore the goal of the milk industry to minimize the plant cleaning times, maximize the production times and simultaneously save operational costs, water and energy. Project MicroMilk – microwave pasteurization Within the EU-funded project MicroMilk a Pan-European con- sortium of small and medium-sized dairy equipment, micro- wave technology and automation technology companies, two research institutes and one university have developed prom- ising technology for the heating of milk by microwaves. Be- cause of the volumetric energy charge, the MicroMilk technol- ogy operates very efﬁciently. As there is no heat exchanger interface in this direct heating process, the formation of de- posits is minimized. Process development and test facility After an analysis of current heating processes, various con- cepts for the microwave heating of milk were developed, tested and optimized using numeric simulations. The primary criterion for development was fast and regular heating. A test facility was designed, developed and constructed and initial test runs were carried out at a laboratory dairy in the Universi- ty of Hohenheim, in order to validate principles of the process and determine data on the process parameters. Industrial prototype Based on the results of the test facility, an industrial prototype for microwave pasteurization was designed, in cooperation with the project partners from industry and using the QFD methodology. Aside from aspects of production and materials technology, the HACCP and GMP Directives for food technol- ogy devices were considered as decisive criteria, in order to enable instant integration into a production. The central task for the product “Milk” was to maintain the microbiological, nutritional and organoleptic quality while still improving the shelf-life of the milk. The system has a modular construction so that it can be both retroﬁtted in existing systems, as well as being applied as a stand-alone system. Quality features and advantages We were able to examine relevant quality characteristics by benchmark comparisons between conventional indirect heat- ing and microwave heating using analytical reference meth- ods. To this end, microwave test facility was integrated into an existing pasteurization system at the research dairy at the 1 2 MEDICINE

2012|13 Annual Report Fraunhofer IGB

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