Has anyone found advantage from sero-typing Listeria monocytogenes?

Hi all,
i am wondering if anyone has found any advantage from sero-typing Listeria monocytogenes? I have a client who had an outbreak recently and one of our government agencies is suggesting serotyping as a method of identifying the source of the contamination. I am not sure that this is worthwhile since Listeria is ubiquitous in the environment and I am fairly certain that the outbreak was due to poor cleaning of equipment.

Serotyping is worthwhile if you are getting regular Listeria isolations and want to find out if the source is raw materials coming in or if your plant environment has been colonised (Listeria loves to hang out in the drains). The results tell you which isolates are the same so you can tell if the serotypes from the drains are the same as those from the product and it's time to steam clean them/ tell the cleaners to stop hitting the drains with hoses!

PCR fingerprinting also allows the identification of like strains and may be a few pounds per test cheaper.
HTH Mike