I don't have a huge experience with Roaches, but in general, if you keep feeding to a minimum (less than the worms would normally eat- it won't hurt them for a few weeks), feed little and often, and cover the food with fresh bedding (which they will eat anyway), the worms should consume the material before vermin are attracted. Yuu could also put some natural fragrance like lavender oil around the outside of the box to confuse/ deter them.