§ Mr. Peter BottomleyTo ask the Secretary of State for Health how many strains of listeria monocytogenes are known to her Department; and what assessment has been made of whether each strain of listeria monocytogenes has the same potential effects on health.
§ Mr. SackvilleThere are 13 main types—serovars—of listeria monocytogenes, each containing a number of strains. All strains contain virulence genes. This means that they all have the potential to cause human illness, although not all are reported to have done so.