it is always safer to buy live feed from garden centers and local fish stores/bait shops...........I have , on several occasions, picked up a worm in my backyard and fed it to my fish..........Personally, I feel like it is picking food off of the floor and feeding it to fish..........I rather spend the $5 that gets me a few dozen worms than having to be paranoid if there is some parasite or pesticide in my feed..............
That is a very good point, I don't mind spending a bit of money for peace of mind.