1. Department of Food Science, Swedish University of Agricultural Sciences (SLU) P.O. Box 7051, 750 07 Uppsala, Sweden.
2. Swedish National Food Administration, Uppsala, Sweden.
3. Corresponding author. Phone: +46 (0)18 67 20 45. Fax: +46 (0)18 29 95. E-mail: Per.Aman@lmv.slu.se