The FDA is telling people to release captive turtles into the wild? If so, this is really irresponsible and something you don't want to do. It wasn't illegal for you to buy the turtle, but it was illegal to sell it to you (unless you signed something saying the turtle was for educational purposes). You have nothing to be worried about.
The turtle-shaped water conditioner will not help with salmonella, but I really don't think you have to be overly worred about getting it if you take a few simple precautions as mentioned above (and in response to one of your earlier posts)--keep your turtle healthy with a good habitat and diet and wash your hands thoroughly if you handle your turtle or any of his things. I also wouldn't clean your turtle's things where food is prepared (i.e., the kitchen sink). And since I think your son is 3, I would have the turtle be a pet to watch, not touch.
Turtles carry salmonella in their intestines and release it when they're sick/stressed. So keeping him healthy is important (and a healthy turtle is a happy turtle).
Read the responses to your earlier post (yesterday) for information on what your turtle needs to thrive. Good luck. Don't worry so much.
BTW, should you need a herp vet and don't know of one, go to the sticky on locating a vet in the Urgent Care Forum and try to find one from the links there.
"You become responsible, forever, for what you have tamed." -Antoine de Saint Exupery-