1. Laboratory of Physical Chemistry and Colloid Science, Wageningen University, Dreijenplein 6, 6703 HB Wageningen, The Netherlands, Laboratory of Microbiology, Wageningen University, Hesselink van Suchtelenweg 4, 6703 CT Wageningen, The Netherlands, and Department of Biomedical Engineering, University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands