Acknowledgements
This work was supported by the Bavarian State Ministry of
Environment and Public Health (Grant no. Az. StMUG: 47d-
G7131-2008/46-6) within the project ‘LENA’ on Nanotechnolo-
gy related Food Safety coordinated by the Bavarian Authority
for Public Health and Food Safety (LGL). The authors would
like to acknowledge G. Wolz for assistance with the
measurements.