[1] Rakuno Gakuen Univ, Sch Vet Med, Dept Hlth & Environm Sci, Lab Food Microbiol & Food Safety, 582 Midorimachi, Ebetsu, Hokkaido 0698501, Japan
[2] Sapporo Med Univ, Dept Microbiol, Sch Med, Sapporo, Hokkaido, Japan
[3] Sapporo Med Univ Hosp, Div Lab Med, Sapporo, Hokkaido, Japan
[4] Sapporo Med Univ, Dept Infect Control & Lab Med, Sch Med, Sapporo, Hokkaido, Japan