1. Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.
2. Institute of Hygiene and Technology of Food of Animal Origin, Ludwig-Maximilian University, Munich, Germany.
3. Federal State Organization, Leningrad Interregional Veterinary Laboratory, Saint Petersburg, Russia.
4. Department of Food Science and Hygiene, Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Tartu, Estonia.
5. Institute of Food and Environmental Hygiene, Faculty of Veterinary Medicine, Latvia University of Agriculture, Jelgava, Latvia.