Dr. David Waagner, associate professor of pediatrics at Texas Tech Medical Center, said eggs should be thoroughly cooked before decorating begins. Eggs have pores in the shell. When infectious bacteria come into contact with the shell, they can get into the egg itself. When the eggs are cooked and the decorating begins, make sure the eggs are not cracked, and dye the eggs only with commercial food dyes and colorings that are safe to eat. When you dyed the Easter eggs in the past, you may have noticed dye managed to get into the egg itself.
Bacteria act just like the dye in that it can go across the eggshell and into the egg.
Easter eggs that are boiled and dyed should be kept inside a refrigerator. Eggs kept outside of a refrigerator for more than an hour should be used for decorative purposes only. If you are going to have kids eat Easter eggs, go ahead and make a separate batch and keep them in the refrigerator. Those are safe to eat. When hiding Easter eggs, avoid areas where the eggs might come into contact with any types of animals, insects and lawn chemicals.