Can anyone recommend a foot deodorant for babies (if it exists, safe to use)?

I wouldn't use foot deodorant either. It can't be a bad as an adult's smelly feet now can it? I mean, I haven't met a baby whose feet is so stinky that deodorant is needed. Keep baby's feet clean and dry. Get your baby shoes that can "breathe" and if it's not necessary (at home for example), baby does not need to wear shoes. If your baby's shoes are the problem, you should air them regularly or get a shoe freshener to keep the shoes from being odorous.