1. Department of Preventive Environment and Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
2. Faculty of Marine Biosciences, Fukui Prefectural University, Fukui, Japan
3. Department of Microbial Control, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
4. Laboratory of Veterinary Public Health, School of Veterinary Medicine, Kitasato University, Aomori, Japan