From prior experience from massive chain pet stores, most of the things workers do (if they even are allowed to) is following a strictly written protocol. Unfortunately, going to get a job at that pet store probably won't do those animals any good.
I'm not so sure about if any parasites or diseases the snakes/reptiles/amphibians have will hitch a ride on you. Though workers don't handle the snakes frequently, if at all, and if they do, it's at the customer's request.