Why Europeans Don't Have To Refrigerate Eggs

International travel is bound to make you feel a bit out of place, but Americans abroad in Europe might be surprised to find how much that manifests at the grocery store. For starters, Europeans don't refrigerate milk, but equally as shocking are the open, unrefrigerated shelves stocked with cartons of eggs. They're right out there in the open, yet often go unnoticed by American shoppers because it's the last place we'd expect to find them. On the flip side, international travelers visiting the United States are bound to be baffled by the fact that we have banished all our eggs to the chilly depths of the fridge.

The U.S. is not the only country where refrigerated eggs are the standard. Japan and Canada do the same, and there are even European nations where eggs go in the refrigerated section, including the Netherlands and much of Scandinavia. However, these nations are in the minority, with unrefrigerated eggs being predominant in every other corner of the globe.

This is not a mere matter of choice. Theoretically, one could refrigerate any eggs they want, but you cannot leave eggs from the U.S., Japan, or any of the other fridge-favoring nations sitting out at room temperature. That's because eggs sold in these countries are washed before sale, stripping away the protective membrane surrounding them and leaving them vulnerable to bacteria. Refrigeration is a precaution that makes up for that, but the big question is: Why do some countries bother to wash eggs in the first place?

A hundred years ago, washing eggs was a fairly common practice in much of the world, but if it isn't done just right, there can be serious consequences. The absence of the outer membrane, which is made of proteins and technically known as the cuticle, leaves the egg vulnerable to bacterial invasions. These risks eventually caused egg-washing to decline in Europe, particularly after a shipment of eggs from Australia to Britain turned up completely rotten.

The resurgence of egg washing in the U.S. and select other countries was spurned by concerns about salmonella. The Centers for Disease Control and Prevention estimate that there are 1.35 million cases of salmonella infections in the U.S. each year, resulting in 420 annual deaths. Eggs are particularly at risk from contamination, as the salmonella bacteria can enter eggs in two ways. It can be transferred to the egg from its mother, or it can permeate the egg's shell from the outside.

In the 1970s, the USDA developed technology to ensure safe and consistent washing of eggs, and it made doing so mandatory for all American egg producers. The process begins immediately after the egg is laid, using hot water and a sanitizing rinse. Once washed, the USDA recommends that all eggs be kept refrigerated at 40 degrees Fahrenheit or lower to prevent a salmonella infection.

The difference between countries that wash and refrigerate their eggs and those who don't comes down to two very different approaches to the salmonella problem. As mentioned, salmonella can infect eggs either internally or externally, and the wash-and-refrigerate method favored by the U.S., Japan, and their cohorts focuses mostly on the external threat. In other countries, hens are vaccinated against salmonella to prevent them from passing it along to their eggs, while producers rely on the natural membrane surrounding the egg to protect it from the outside.

Washing eggs removes the cuticle, which is why they must be refrigerated afterwards. Another precautionary measure is coating the washed egg in a thin layer of oil to cover pores and cracks in the shell. However, according to medical journal The Lancet, the U.S. has a higher rate of salmonella infections than most of Europe, and after a serious salmonella outbreak in 2010, some American egg producers began vaccinating their hens against salmonella too. This won't put an end to our egg-refrigerating ways, as this remains a legal mandate for egg producers, but it does mean double protection against salmonella. As a bonus, refrigeration increases the shelf life of an egg from 21 days to around 50 days, which means more time to perfect your scrambled eggs.