This Is Why Eggs Are Refrigerated in the US
Visiting the grocery store in a foreign country is one of the best ways to get a sense of the place. You may have noticed, while perusing the aisles in Europe or Asia, that other countries don’t store eggs in the refrigerator. It’s just one of the dairy-aisle products for which there isn't a universal storage method (see also milk), and it's worth noting that the United States is in the minority when it comes to only selling refrigerated eggs. But before you get into a heated debate about which egg-storage method is superior, know that in the US, you have to refrigerate eggs. Unless you are personally acquainted with the chickens that laid them, keeping eggs at room temperature simply isn’t an option here.
The United States Department of Agriculture requires egg producers to clean and sanitize eggs. All of the eggs that you buy in a grocery store are washed—literally washed with soap and water—and the egg washing process removes the dirt and fecal matter that might carry salmonella. With the dirt, though, the washing process removes the egg’s outer protective layer. Without this layer, the washed, and now porous eggs, must be kept in an environment cooler than 45 degrees Fahrenheit. Otherwise, condensation can build on the egg, which would allow any salmonella on the outside of the egg to enter the shell and affect the part of the egg that we eat. Refrigeration also prevents the growth of salmonella that may already be inside the egg—salmonella that can be transferred from the reproductive tract of the hen to the egg.
So how are other parts of the world able to take their eggs straight from hen to grocery store shelf to kitchen counter? Most countries (Japan, Australia and Scandinavia are exceptions) don't wash their eggs and the protective layer remains intact. In fact, some countries ban egg washing outright because the egg’s outer layer, also called the cuticle or bloom, prevents bacteria, from entering the egg’s shell. These countries believe that the egg's natural, protective layer more effectively wards against salmonella than washing eggs does, and that by not washing eggs, farmers are motivated to produce the cleanest eggs possible.
Poultry husbandry methods in the US, however, often put eggs at risk of coming in contact with hen feces, and feces carry salmonella bacteria. Until that changes, refrigerating eggs is really a small inconvenience to trade for freedom from disease. Plus, when a recipe does call for room temperature eggs, it's fine to let eggs sit out for an hour to bring them up to optimal temperature. No harm, no ...fowl.