Do eggs really need to be refrigerated?

Nothing beats a plate of freshly-prepared eggs, but before they found their way to your table, they were probably hanging out inside your fridge. You may have heard, though, that people in some other countries do not refrigerate their eggs. So what gives? Do eggs really need to be refrigerated? That depends where you're buying your eggs.

All eggs graded by the U.S. Department of Agriculture (USDA) that you find in your local grocery store are required to be cleaned after they're collected, and this includes washing and sanitizing. This act removes a very thin, naturally-protective layer from the surface of the shell (it's called the "bloom," or cuticle), which functions as a protective barrier — it keeps oxygen inside the egg, and helps keep bacteria out. Without this layer, bad germs can find their way inside the egg through its porous shell, and at room temperature that bacteria can multiply quickly, which is why the USDA, the CDC, and just about every official agency in the U.S. says that refrigerating eggs is the only way to keep them in your home safely. 

The main bad guy in the egg world is salmonella, which can cause an illness that can last up to a week and includes awful symptoms such as diarrhea, vomiting, fever, and cramps. Salmonella can be more serious for certain populations, including the very young, the elderly, and those with weakened immune systems. In other words, nobody wants salmonella, and there are policies in place to minimize this possibility. 

The USDA notes that when you buy eggs at the store, you should only buy already-refrigerated eggs and avoid those with cracked or unclean shells. Keep eggs in your fridge until you're ready to cook them, and don't store them in those cute little egg holders in the door — pick the coldest part of your fridge instead. 

Eggs can live outside your fridge for a short time, but the USDA recommends they not hang out there for more than a couple of hours. Cold eggs can "sweat" when out of the refrigerator, which can draw bacteria inside the egg.

What about farm fresh eggs, though? Picking up a few dozen from your local farmer's market (or out of your own coop in your yard) probably makes you wonder if a trip to the fridge is even necessary. Happy news, here — the answer is no. That bloom we talked about earlier? It isn't washed away in these situations, because they're not going to go through the process of USDA grading and they won't be visiting the store. However, keep in mind that they don't last anywhere near as long on your counter as they will in the fridge, so if you're not going to use them in a day or two, just pop them in the fridge.

If you visit another country and find eggs that are not in the refrigerated section, it's because that country doesn't have laws about washing and sanitizing eggs after they're collected, so they still maintain that protective layer. Just don't bring this habit back home with you after your trip — once an egg is refrigerated, it has to stay that way.