The dye in the food really annoys the heck out of me! What are the manufacturers thinking?! I'm sure my cats would not care if their food was purple with yellow stripes. Everyone who has ever had a cat knows about their hair-trigger gag reflexes. If it wasn't on the quilt blocks, it might have landed on carpet or upholstery, which could have been even harder to fix, if that's any consolation. Sorry you're having to cope with this.
One thing you could try before giving up and redoing them is soaking one in hydrogen peroxide. If it's an organic dye, that might work. It also might bleach your fabric, so don't go all out until you know.