1. Department of Veterinary Microbiology, Royal Veterinary and Agricultural University, 1870 Frederiksberg C., Denmark1;
2. Laboratorium voor Microbiologie, Rijksuniversiteit Gent, B 9000 Ghent, Belgium2
3. Department of Food Science, Universiti Putra Malaysia, 43400 Serdong, Selangor D.E., Malaysia3; and