I have a Pacman frog and he eats worms. I buy worms (red wigglers) from the pet stores around here to feed him/her, but they are frequently out of stock and there aren't any small local pet stores in my area that carry feeder insects, they are just dog and cat specialty stores. So I usually have to supplement with gut loaded crickets, which is fine, but I know worms are more nutritious.
My question is- is it ok to go to the store and buy bait worms? If so what kind? I have read to avoid certain ones because they add dyes to them, but I am not sure which ones to look out for. Could I also go get worms from my own yard? I am concerned that worms from outside would have parasites or something... I need advice because my frog loves worms!!

Thanks in advance for anyone's help!