1. Biotechnology Department, Research and Development, Roche Vitamins AG, CH-4070 Basel, Switzerland
2. BCCMTM/LMG Bacteria Collection, Laboratory for Microbiology, Ghent University, K.-L. Ledeganckstraat 35, 9000 Ghent, Belgium
3. TNO Nutrition and Food Research, PO Box 360, 3700 AJ Zeist, The Netherlands