Do they know something we don't, or what?
Why Do We Refrigerate Eggs in the U.S. but Not in Europe?
Published on Jun. 30, 2025
From using the imperial system instead of metric to driving on the opposite side of the road, we do things a bit differently in the United States than they do them across the pond. Some of these are easy to explain, while others just leave us confused. Case in point: Why do we refrigerate eggs when Europeans store them at room temperature? Make it make sense!
Putting eggs in the fridge sounds completely normal to us, but there has to be a reason people in Europe just stick them in the pantry. Reader’s Digest spoke to Martin Bucknavage, a senior food safety extension specialist in the food science department at Penn State University, to explain what the heck is going on with eggs over there on the continent. Keep reading to find out.
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Why do we refrigerate eggs in the U.S.?
“There are two primary reasons we refrigerate eggs,” Bucknavage says. “To reduce spoilage and prevent the growth of salmonella, if it were present.” According to the USDA, eggs will keep for three to five weeks in the refrigerator after purchase, even if that takes them past their sell-by date. That means refrigerating eggs gives you a chance to use them all before they go bad, even if you only cook with eggs once or twice a week.
But the bigger reason we refrigerate eggs is to prevent salmonella. “Salmonella infection is one of the leading causes of bacterial foodborne illness in the U.S.,” explains Bucknavage. Because eggs have historically been a source of salmonella contamination, Bucknavage says there have been “ongoing initiatives to reduce this, including washing eggs and ensuring proper refrigeration.”
What part of the egg can be contaminated?
Bucknavage says eggs can be contaminated on the surface of the egg’s shell or inside the egg. Here in the U.S., we address potential contamination on the eggshell through a washing and sanitization process (more on that below), and we refrigerate eggs to slow the growth of salmonella inside the egg, if it’s present. According to a CDC report, refrigerating eggs immediately after packing or laying could reduce illness from salmonella by roughly 10%.
It’s also important to note that there are additional measures taken before chickens lay eggs to prevent salmonella contamination, such as routine testing and monitoring flocks for outbreaks.
How does the sanitization process work?
It’s essentially a power wash. “Per the USDA, modern egg washers use pressure sprays, rotating brushes and an egg-spinning device that increases contact between the egg and the brush and minimizes damage to the egg,” Bucknavage explains. This process is highly effective for removing any surface contamination from the eggshell, but it does leave it more vulnerable to contamination.
That vulnerability comes from the loss of the cuticle, which is the thin, protective membrane that covers the egg and helps prevent bacteria from penetrating the shell. Washing “removes the cuticle from the egg [and] makes the egg more susceptible to contamination, so refrigeration becomes more important,” Bucknavage says. Indeed, eggshells are more porous than you might think. Refrigerating them after they undergo this sanitization helps ensure that no new bacteria grows.
How does this differ from what European countries do with their eggs?
In European grocery stores and homes, eggs are kept at room temperature. Why? “The European Union does not require eggs to be washed, so the cuticle is still in place helping to prevent contamination,” Bucknavage says. Because washing removes the cuticle, doing away with the egg’s natural protective covering, refrigeration is necessary. But the EU doesn’t use this same washing process and instead leaves eggs just as they are, so they don’t see the need for refrigeration.
What’s the risk of egg contamination in Europe?
“There is debate over which is better, washing or not washing,” notes Bucknavage. That said, studies show that eggs and egg products remain the foods associated with the most outbreaks of salmonella, both in Europe and in the U.S. And in both places, bacterial contamination inside the egg was more often the cause than bacteria on the egg’s shell, so it’s unclear if one method is superior to the other when it comes to preventing contamination.
One thing that does seem clear, though, is the benefit of refrigeration. “You can refrigerate eggs that have not been washed, and this is useful for reducing rate of spoilage and growth of salmonella if it should be present,” Bucknavage says. Indeed, studies have also found that storing eggs at a temperature below 46 degrees inhibits the growth of salmonella in egg yolks, which is the part of the egg where the bacteria can multiply the fastest.
Also smart: If you do decide to refrigerate eggs that have not been washed (which you can get at farmers markets here in the U.S.), it’s a good idea to keep them there. “If you take them back to room temperature for storage, condensation can form on the eggs in which the surface moisture is not desirable,” says Bucknavage. “Bacteria traversing the egg shell is more likely when the eggs are wet.”
Is this similar to the reasons milk and butter aren’t refrigerated in Europe?
In some ways, yes. As with eggs, milk processing in Europe differs slightly from what we do in the U.S.
Bucknavage says it’s more common in the EU to use what’s called aseptic processing, which is a high-temperature treatment followed by a transfer to a sterile container. According to the American Dairy Association, heating milk to 280 to 300 degrees for two to six seconds—called ultra-high temperature (UHT) pasteurization—will kill any harmful bacteria in the milk. Bottling it immediately after pasteurization in air-tight, sterile packaging makes the milk shelf-stable for several months until you open it.
But in the U.S., we typically use high temperature short time (HTST) pasteurization, which means heating the milk to 161 degrees for 15 seconds. Instead of resulting in shelf-stable milk, this method requires that the milk be refrigerated and consumed within one to two weeks. “This is more of a customer preference thing,” Bucknavage says. “In the U.S., people prefer to buy milk that is refrigerated.”
Butter storage is also more of a personal preference. While refrigerated butter will generally last longer before going rancid and tasting bad, butter stored at room temperature isn’t likely to make you sick. That’s because illness-causing bacteria need protein, and butter is mostly fat—at least 80% fat in the U.S., to be exact. In Europe, butter must be between 82% and 90% fat, which creates an even more hostile environment for bacteria, and thus a safer one for room-temperature storage. Still, if you want your butter to last, you should only take some out of the fridge at a time.
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Sources:
- Martin Bucknavage, senior food safety extension specialist in the food science department at Penn State University; email interview, June 26, 2025
- USDA: “How long can you store eggs in the refrigerator?”
- Emerging Infectious Diseases: “Salmonella Enteritidis Infections, United States, 1985–1999”
- Comprehensive Reviews in Food Science and Food Safety: “Salmonella in eggs: From shopping to consumption—A review providing an evidence-based analysis of risk factors”
- American Dairy Association: “What is aseptic milk?”
- American Dairy Association: “What is pasteurization and why do we use it?”
