Sorry but that's just wrong. Please see www.barefooters.org and particularly "Bare Feet and the Dept of Health." Please don't unwittingly spread unsubstantiated myths.

I think it has more to do with safety, for the bottom and tops of the feet.....employees of much or all of the work establishments require employees to wear shoes with toes. You will hardly see a large store or resturant facility that has employees wearing open toe shoes. It is actually an osha law. Not health dept. law.
That is so no one can claim something fell on their toe, or that they stepped on a piece of something...anyway you get the idea. They dont want to be sued...so if your employer says no open toed shoes thats the reason...now as for the public coming in barefoot..well, they are used to the old slip and fall routine..they dont want you screaming......"I stepped on a piece of glass...what are you going to do for me?i.e.$"
(I work in the safety profession, and yes it is a viable reason for this rule, unless you want to sign a release when you walk in the door.) Now as far as health and safety issues...
fungus...there is very little fungus growing on the outside of shoes. But fungus is under nail beds and in under the skin of feet of people who have say..atheletes foot.
Its not to say everyone has it, but establishments like grocery and resturants do fear that,along with body lice and crabs..
Now of course the argument is, people dont eat off the floor or sit and play on the floor so who knows what is on there anyway. I dance barefoot, but have to say...I dont think I want barefeet in resturants myself..