Is It Safe To Store Eggs At Room Temperature?

Or do they belong in the fridge?

eggs in a carton
Photo: Caitlin Bensel; Food Styling: Torie Cox

In supermarkets throughout the United States, eggs are typically kept in refrigerator cases, and after returning home from a shopping trip, most American home cooks transfer their egg cartons straight from their shopping bags into their fridges.

But anyone who's ever studied abroad or traveled in Europe tell you that refrigeration isn't the norm for egg storage in that part of the world. Which raises the question: Is it unsafe to keep eggs at room temperature? Or is the American tendency to refrigerate eggs just a force of habit?

We turned to a pair of experts to provide some helpful answers and advice on egg refrigeration: Colorado State University instructor, Ph.D candidate, and food science writer Caitlin Clark of Robust Kitchen and former city health inspector and current food safety consultant Francine Shaw of Savvy Food Safety.

Storing eggs at room temperature isn't advised in the United States because of Salmonella and other pathogens.

When we asked Clark whether it's safe to keep store-bought eggs at room temperature in the U.S., her answer was a clear "no."

"This has to do with how the U.S. manages the risk of Salmonella, a common foodborne pathogen," Clark continued.

She tells us that "eggshells are porous, which is necessary for gas exchange as the embryo inside develops. Just before the egg is laid, it becomes coated with a foamy layer of protein called the 'bloom' or 'cuticle'. The bloom seals the pores, preventing bacteria from reaching the nutrient-rich environment inside."

Because chickens in the United States aren't vaccinated against Salmonella, commercial farms need to immediately wash the eggs upon harvest to "remove the heavy loads of Salmonella (and other bacteria) that are passed to the eggs from the infected hens."

Unfortunately, that washing process "also removes the bloom, [which means that] the eggs have no further protection from the environment. If the vulnerable, porous eggshells encounter bacteria during their long journey from the farm to your pan, these pathogens can penetrate the egg and grow very quickly if their growth is not slowed by refrigeration."

Room-temperature eggs dry out more quickly than refrigerated eggs, which can compromise their nutritional value.

In addition to the safety concerns posed by Salmonella and other bacteria, keeping eggs at room temperature can have negative effects on their protein content.

"Eggs stored at room temperature dry out and lose protein quality, even when they remain microbiologically safe to eat. However, eggs stored in the fridge maintain their moisture and nutritional [value]," Clark tells us.

Clark also points out that prolonged exposure to "warmer" (aka non-refrigerated) temperatures can reduce the longevity of an egg: "Eggs are simply made of chemical compounds that degrade over time, even in the best conditions. Cold temperatures slow this degradation, extending their shelf life. This is why eggs last two to three weeks longer in the fridge [than they would at room temperature]."

The only eggs that can be kept at room temperature are freshly-harvested eggs that haven't been washed and processed.

While store-bought eggs should always go right into the refrigerator, there is a bit of wiggle room where farm-fresh eggs are concerned. Because these eggs haven't been commercially washed, they still retain their "bloom," which gives them more protection from bacteria than grocery store eggs would have.

"Farm fresh eggs with the cuticle or bloom still intact can last several days at room temperature," says Shaw.

That said, Salmonella can still be present in eggs that still have the bloom attached. Therefore, for the safest results, Shaw does recommend refrigerating freshly-harvested eggs.

If you're determined to keep eggs at room temperature, store them in a cool, dry place.

For those who choose to keep their farm eggs at room temperature, Clark advises avoiding direct sunlight and sticking to an area with low humidity.

"Store the eggs in or on something absorbent (like cardboard or a paper towel). Any moisture collection on the surface of the egg can be dangerous and will further reduce its shelf life," Clark says.

If you gave your eggs a particularly vigorous over-the-sink scrubbing and are concerned that you might have compromised the bloom layer, "a light coating of mineral oil is a good substitute," Clark says.

Keep in mind that this doesn't apply to commercially-washed eggs, as mineral oil can't compensate for the chemical changes caused by an industrial-strength cleansing process.

Never store previously-refrigerated eggs at room temperature.

Whether we're talking about store-bought eggs or farm-harvested eggs, once an egg has been stored in the fridge, there's no going back.

"Once previously-cold eggs begin to warm, condensation forms on the outside of the shell, making an incredibly rich broth for any bacteria present on the surface of the egg. It also provides a path [that allows] bacteria to 'swim' through the porous eggshell directly into the interior of the egg. This is especially problematic in the case of eggs that have not been washed, but it is an issue even in washed, sanitized, store-bought eggs. Once an egg of any kind goes in the fridge, it must stay there until you are ready to eat it," Clark insists.

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