1. Department of Food Hygiene and Environmental Health, University of Helsinki, Helsinki, Finland
2. Department of Mathematics and Statistics, University of Helsinki, Helsinki, Finland
3. Microbiology Laboratory, Istituto Zooprofiilattico Sperimentale delle Venezie, Villorba, Italy
4. National Veterinary Institute, Uppsala, Sweden
5. National Reference Center for Anaerobic Bacteria and Botulism, Institut Pasteur, Paris, France
6. Department of Computer Science, University of Helsinki, Helsinki, Finland