Back when I wrote a couple of posts about egg refrigeration, I mentioned egg bloom quite frequently and promised an explanation later. Well, later has arrived so here is an explanation:
Egg bloom is the protective layer chickens internally coat their shells with that seals the pores of the egg to prevent contamination from bacteria and to help prevent moisture from escaping. This is all to ensure that the egg lasts as long as possible. It’s really amazing if you think about it. It’s just another way for Mama Hen to keep her eggs safe from harm and in turn it helps us.
Provided that bloom is still surrounding the egg, this is one of the reasons why I feel perfectly safe eating an unwashed egg from my backyard. I only wash them if they’re actually dirty and then they go in the fridge or are used right away.
Commercially, eggs are washed right away and then coated with oil. This doesn’t make a lick of sense to me, but I know most people who have never seen a farm animal in their life would prefer a washed, shiny egg versus a possibly dusty, matte egg that might have a feather sticking to it. This seems to me to be yet another example of our germaphobic culture, but that’s another story for another time.
Just like factory milk, we tend to hear a lot of scary stories about salmonella outbreaks in eggs. Where do these eggs come from? Generally from chickens raised in poor conditions (Ever visited someone who lives on a commercial chicken farm or close to one? Ugh!) these eggs are first given a chemical wash to remove dirt and the bloom, then recoated with a sort of ‘synthetic bloom’ as I think of it, which is mineral oil. Between the washing and the recoating and the already ill chickens, do these commercial eggs really stand a chance to be safe by the time they make it to the store?
Aside from chemical and bacterial invasions, though, the bloom also prevents the nutrients from escaping! If the bloom is intact there is no exchange of gases or evaporation of vitamins. No oxygen is getting into that egg, or in such small amounts that they’re miniscule. The egg will last longer and be healthier for you in the end. Once the gas exchange occurs, your egg starts to slowly rot and will not last half as long as it’s unwashed counterpart.