Thomas Kunz (1), Hans-Joachim Cappius (2), Antje Fröhling (3), Andrea Karrasch (4), Michael Kumke (5), Frank-Jürgen Methner (1), Peter Thoren (6), Andreas Walte (7); (1) Technische Universität Berlin, Chair of Brewing Science, Berlin, Germany; (2) Laser- und Medizin-Technologie GmbH (LMTB), Berlin, Germany; (3) Leibniz Institute for Agricultural Engineering Potsdam-Bornim e.V. (ATB), Potsdam, Germany; (4) LLA Instruments GmbH, Berlin, Germany; (5) University of Potsdam, Institute of Chemistry, Physical Chemistry, Golm, Germany; (6) Röber Institut GmbH, Wutha-Farnroda, Germany; (7) Airsense Analytics GmbH, Schwerin, Germany

Malt and Grains


 Mycotoxins are toxic and suspected to be carcinogenic and mutagenic, to influence the endocrine system negatively, to promote bleeding, to weaken the immune system, to damage skin and kidneys and to attack the nervous system. In worst cases mycotoxins can pass undetected through the whole production chain of grain and cereal products and damage the health of humans and animals even in low concentrations. The aim of the Optiscreen research project is the development of a screening concept to detect mycotoxins in storage sides and to improve the elimination of contaminated grain during industrial grain sorting. The optical sensor for 100% detection above a grain stream will enable contaminated grains to be sorted out and will be supplemented with an ion mobility spectrometry (IMS) sensor for the analysis of the gas phase in grain silos for early and quantitative detection of fungal contamination. For the development of the described screening sensor system several fundamental investigations are necessary. First, presented results demonstrate the identification of spectral optical regions of contaminated grains in comparison to microbiological analyses and quantitative mycotoxin determination via ELISA and HPLC. Fluorescence in combination with NIR reflection spectroscopy is applied in the optical sensing. The microbiological results give information about the microbial load of grains, including specific fungi contamination in correlation with the mycotoxin content and, in general, are used for the calibration of the sensor system. The experimental optical data will be treated in-line by chemometric signal processing to improve the identification of contaminants. Finally, a demonstrator is constructed which in turn will be tested for sensitivity under laboratory conditions. In the second approach, IMS is evaluated for the screening of specific fungi-related metabolites products in the gas phase. For the determination of fungi species, selective metabolite model investigations with different fungi bred on agar and brewing barley are performed with respect to the characteristic volatile metabolites. The headspace analysis is performed using SPME/TD for sampling and GC-MS for the determination of the metabolites. Based on the metabolite pattern analysis information on fungi species and their respective approximate quantity, possible contamination of grain storage sides will be monitored by analysis of the gas phase.

After qualifying as a certified technician in preservation engineering (1991-1993), Thomas Kunz completed his basic studies in chemistry at the University of Applied Sciences, Isny (1994-1995) and his basic studies in food chemistry at Wuppertal University (1995-1998), before starting to study food technology at the University of Applied Sciences, Trier (1998-2002). After graduating, he worked as a chartered engineer in the area of ESR spectroscopy at the Institute of Bio Physics at Saarland University (2002-2004). Since 2005 he has been employed as a scientific assistant, Ph.D. student and since 2009 as head of the laboratory at the Institute of Food Technology and Food Chemistry, Chair of Brewing Science, Technische Universität Berlin. His main research focus lies in analyzing radical reaction mechanisms and oxidative processes in beer and other beverages using ESR spectroscopy. A further research focus consists of the optimization of filtration and stabilization processes.