1. Laboratory of Food Microbiology and Food Safety, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
2. National Veterinary Assay Laboratory, Ministry of Agriculture, Forestry and Fisheries, 1-15-1 Tokura, Kokubunji, Tokyo 185-8511, Japan
3. Department of Veterinary Internal Medicine, Tottori University, Minami 4-101, Koyama-cho, Tottori-Shi, Tottori 680-8553, Japan
4. Division of Bioresources, Hokkaido University Research Center for Zoonosis Control, Sapporo, Hokkaido 001-0020, Japan