Otherwise, there is no telling what additives and dyes are in those filaments, or what they do to a child after prolonged exposure.
You could say this about most plastics. If you are concerned about PLA purity you should be triple scared of the much worse plastics we use regularly.
I wouldn't make a pacifier or chew toy from it, but I've got no problem making dozens of PLA toys for my kids (after having done the research on the filaments), and I'd say 50% of the toys my kids have, have been 3D printed by ourselves.
(And if you do that, you're already screaming 'not food safe' any time anybody mentions 3D printing anyway.)
Aside from direct and prolonged contact, (you probably don't want to print and repeatedly use a spoon for example) the main somewhat legitimate concern is bacterial growth in all the tiny crevices that arise as a result of the printing process. Don't 3D print food storage jars and try to wash and re-use them?
For a child's toy, there's not really a reason to worry about or treat it differently than anything you buy. Once it's been chucked on the floor, smeared through the dogs breakfast, and stuck in their mouth, it's pretty inconsequential that it happened to be 3D printed.