1 Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan.
2 Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of P. R. China, Department of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China.
3 Department of Microbiology & Immunology, National University of Singapore, Singapore 117597, Singapore. Electronic address: micleeyk@nus.edu.sg.