I am building a couple of support structures for 3D Halloween cakes. My question is what do you cover the PVC and conduit with so the cake does not touch the metal and plastic, but a food-safe material?

use copper made for water lines instead of conduit.

use PVC (usually the white kind) that is rated for drinking water DELIVERY.

both are food safe with one catch -- cooper should not be in contact with high acid foods -- but then I don't think you're using tomatoes are you?

Thanks for the quick reply!