1. Institute for Prevention and Occupational Medicine of the German Social Accident Insurance Institute; Ruhr-University Bochum (IPA); Bürkle-de-la-Camp Platz 1 44789 Bochum Germany
2. Institute and Outpatient Clinic of Occupational, Social and Environmental Medicine; University of Erlangen-Nuremberg; Schillerstrasse 25 and 29 91054 Erlangen Germany
3. Department of Food Chemistry and Toxicology; Institute for Applied Biosciences; Karlsruhe Institute of Technology (KIT); Adenauerring 20a, Geb. 50.41 76131 Karlsruhe Germany