In the United States, after the eggs are laid by the chickens, they go through a cleaning process. The eggs are washed in warm water and a detergent. After washing, they are rinsed and cleaned with a sanitizer to remove any remaining bacteria. The eggs are then dried to remove moisture from the surface. The result are eggs that are clean on the outside, and look spotless.
However, washing and sanitizing the outside of the egg removes the eggās cuticle. The cuticle is a natural layer that protects the egg from harmful bacteria getting inside. If the egg had been fertilized, this is how the egg naturally protects the embryo while it is developing. Cleaning the eggs removes the cuticle, so the eggs must be kept at refrigeration temperature. Otherwise, the bacteria could easily enter the egg and multiply to dangerous levels. By keeping it out of the danger zone, salmonella canāt multiply rapidly.