When buying a carton of eggs from the grocery store, one usually does not imagine that their fresh eggs have been given chemical baths to sanitize them. Even in organic egg production, detergents or chemicals may be used as long as they are non-synthetic or on the National List of Allowed and Prohibited Substances.
Allowed cleaning solutions from the list include:
- Potassium hydroxide or sodium hydroxide (lye)
- Sodium carbonate
- Ozone (a brand name disinfectant)
- Hydrogen peroxide
- Peracetic acid—a mixture of vinegar and hydrogen peroxide
Although an eggshell may seem like a hardened exterior preventing anything from getting in or out, it is actually a porous membrane much like our skin, which is why both consumers and farmers are concerned with treating eggs with chemicals—synthetic and non-synthetic alike.
Egg shells are naturally coated in what is called a bloom, a waxy cuticle which prevents bacteria from permeating the yolk. When eggs are fresh and the bloom remains intact (not washed away by chemicals) they do not need to be refrigerated.
Throughout Europe and in many countries around the world, it is uncommon to refrigerate eggs. Like produce, eggs should be eaten fresh and in a short amount of time to prevent spoiling.
In the US, refrigeration became common after the advent of industrial agriculture. Whereas food production used to be localized, mass production consolidated small, family based farms into a handful of large agribusinesses which supply the entire country. Without localized sources, eggs, like many other foods, required a longer shelf life to support cross-country travel and storage time. Shelf life was extended for eggs by instating refrigeration as a common storage method and by coating eggs with mineral oil before packaging them.
High quality eggs are generally processed around seven days. However, the USDA allows processing to take up to 30 days from when they were laid.
Some farmers prefer a more natural alternative to washing their eggs with chemicals.
Mark McAfee, owner of Organic Pastures, described his methods of egg washing. “What we use is tepid water and use no cleansers whatsoever. Any dirty egg we wash off with tepid water with a little egg scrubber, it’s all done by hand, and then they’re placed in a drying rack, then placed in the egg cartons. We don’t use any sanitation, or heating, or irradiation, or chemicals or anything—it’s just clean water, that’s it.”
Other farmers prefer a dry method which does not include the use of any liquids whatsoever. Dry cleaning can be done by simply brushing debris off the eggshell with a brush or loofah-like sponge.