I thought bleach only "hides" the mold but doesn't kill it...
I have wondered the same thing in the past. I stopped buying squirt toys for that exact reason. For all her other bath toys, I bought one of those net thingies that attach to the wall above tthe tub with suction caps. But I actually use stick on hooks, as the suction cups don't work so well. I get DD to empty all her toys and put them in the net before getting out of the tub. I think getting them dry between uses stops them from getting moldy.

Sasa