Health risk if any home whirlpool tubs

I saw some web articles on the "filth" that collects in the piping of home whirlpool type bath tubs- i am trying to get more info- looking for info on home whirlpool or air bath tubs, NOT HOT TUBS. Info relative to infection risk-
Any ideas on where to look?
Thanks

As always, google is your friend. Here is one: http://www.infectioncontroltoday.com/articles/231feat1.html

That article is from 2002, so you need to do more research to find out if (a) any design improvements have been made , or (b) if there are recommended cleaning/maintenance guidelines to reduce the problem.

I buy the stuff at Pool City, or a place which sells pools to clean out the jets. It is simple, just fill up the tub, add the stuff and turn on the jets, I was amazed at how much junk comes out of the them. I also, use a q-tip and clean them, too.