This study was supported by research funding from Kyllikki and
Uolevi Lehikoinen Foundation and the Ministry of Agriculture and
Forestry, Finland (4877/501/2005), and was performed at the
Centre of Excellence in Microbial Food Safety Research, Academy of
Finland (118602, 141140). We thank Jari Aho, Erja Merivirta, and
Anu Seppänen for their technical support.