The last time I visited Italy to see my relatives, I was surprised that my cousins kept eggs sitting on the counter. I kept fighting the urge to put them into the refrigerator as I do in the U.S.—but apparently, it wasn’t necessary.
Why do eggs have to be refrigerated in the United States, but other countries say they are fine at room temperature? It turns out it all depends on what happens to the eggs after they pop out of the chicken. Here’s what I learned from the experts.
Why Eggs Are Refrigerated in the U.S.
Eggs can become infected with salmonella if the bacteria is passed from the hen’s reproductive tract to the eggs as they form. Then, the eggshells can become contaminated after they are laid if they touch the hen’s droppings.
“This is why eggs are required to be washed at processing plants in the U.S.,” explains Ghaida Batarseh Havern, food safety extension educator with Michigan State University Extension’s Health and Nutrition Institute.
Because of concerns about bacteria and egg freshness, U.S. egg producers began washing and refrigerating eggs in the 1970s, according to the United States Department of Agriculture (USDA). Other countries, including Canada and Japan, soon started doing the same.
About 60 percent of eggs that are sold in the U.S. come from processors that take part in the USDA grading system. This is a voluntary process where eggs are graded AA, A, or B depending on the quality of the eggs and how they are cleaned.
“All USDA-graded eggs and most large-volume processors follow the washing step with a sanitizing rinse at the processing plant,” says Batarseh Havern. This is a qualifier to get the top Grade AA or A mark on the egg carton—generally, the higher the grading, the more the eggs cost.
When eggs are washed, the natural protective layer on the eggshell is removed and therefore the eggs need to be refrigerated to keep them safe to eat.
Why Some Countries Don’t Refrigerate Eggs
Throughout most of Europe and across the world, eggs stayed unwashed and unrefrigerated. The belief is that eggs have a protective coating or cuticle that keeps bacteria from being able to make their way through the shell.
“Some European countries say that refrigeration is not required and washing the egg removes the protective cuticle,” says Batarseh Havern. In addition, the cost of cleaning and refrigerating eggs—from the moment they are laid until they are delivered and sold—can be costly.
So Which Way Is Better?
A study published in 2018 in the journal Poultry Science compared common methods of storing eggs. The research found that the method of cleaning and refrigerating eggs followed in the U.S. resulted in the highest-quality eggs when they were stored for 15 weeks.
How To Keep Eggs Fresh
When you bring eggs home from the store, the USDA recommends immediately placing them in the refrigerator. Leave them in the original carton and store them in the coldest part of the refrigerator, not in the door. The carton protects them from breaking and from absorbing odors from other food in your fridge. It also has the “best by” date to help you keep track of freshness.
There’s no need to wash eggs again. Washing them could let dirty water seep into the pores of the egg.
And if you’re making a recipe that calls for eggs to be at room temperature? Never leave them out for more than two hours, advises the USDA.
If You Buy Fresh Eggs From the Farmers Market
If you buy eggs at a farmers market or from a backyard chicken keeper, ask them whether the eggs have been washed. Washed eggs should be refrigerated as soon as you get home. Rules vary by state about whether small producers must wash their eggs. Some producers advise leaving unwashed eggs out of the refrigerator.
“Some markets may require egg washing and then a label. We recommend refrigerating eggs promptly at 40°F as soon as you get home,” says Batarseh Havern. “You may want to bring a cooler with you to the farmers market. For the best quality, use within three weeks of purchase.”