Do eggs need to be refrigerated? Why the US and Europe differ
In the United States, yes: eggs are washed at the packing plant, and a washed egg goes in the fridge and stays there. In most of Europe they are not washed, are not refrigerated in shops, and keep on the counter. Both systems work. What does not work is mixing them.
The reason is a layer on the shell called the cuticle. USDA's research service describes it as "a thin, protective 'cuticle,' or membrane, that prevents Salmonella and other bacteria from penetrating the shell" (How We Store Our Eggs, and Why). Washing an egg takes the cuticle with it, which is why a washed egg needs the cold instead.
What the US system is
American eggs are washed and usually sanitized at the plant. FSIS puts it this way: "most eggs undergo a washing process at the plant; this is often followed by a sanitizing step" (Shell Eggs from Farm to Table).
Refrigeration then runs the whole way to the shop. The rule comes from FDA: producers "maintain storage temperatures of 45 ˚F, beginning 36 hours after the eggs are laid", in USDA's summary of it.
Once you are home, two lines from FSIS matter more than anything else on the subject:
A cold egg left out at room temperature can sweat, facilitating the movement of bacteria into the egg. In addition, any Salmonella in or on the egg will multiply at room temperature. Refrigerated eggs should not be left out more than 2 hours.
That is the answer to "can I leave the eggs out for an hour before baking?" and it is also why a carton bought cold does not become a counter egg by moving it.
What the European system is
In most EU countries, in the same USDA article, "eggs are neither washed nor refrigerated. They are kept at room temperatures, even in stores." The cuticle is left on, and the egg is protected by it rather than by the cold.
A British or German kitchen keeping eggs in a bowl on the counter is not being careless; it is following the system those eggs were packed for. A US kitchen doing the same thing with supermarket eggs is not.
Does refrigeration change how long they keep?
It changes it a lot, and USDA has the numbers from a study of 5,400 eggs over 15 weeks. Refrigerated eggs, "regardless of whether they were washed or oiled, were still Grade A quality after 15 weeks". Unwashed eggs kept at room temperature "degraded from Grade AA to Grade B in just a week" and "lost 15 percent of their weight".
The FSIS storage chart is the practical version, and our storage time lookup searches the companion chart:
| Egg | Refrigerator | Freezer |
|---|---|---|
| Raw eggs in shell | 3 to 5 weeks | Do not freeze in shell |
| Raw egg whites and yolks | 2 to 4 days | 12 months |
| Hard-cooked eggs | 1 week | Do not freeze |
| Liquid egg substitute, opened | 3 days | Do not freeze |
Should you wash eggs at home?
FSIS answers that one in two words and a reason:
No. It's not necessary or recommended for consumers to wash eggs. This increases the risk of contamination because the wash water can be "sucked" into the egg through the pores in the shell.
Farm eggs with something on the shell get wiped dry, not washed, and the same logic applies: water moves through the shell, and dry is the point.
There is one more step in the US system worth knowing, from FSIS's Washing Food page: the coating the plant washes off is "replaced by a light coating of edible mineral oil, which restores protection for long-term home storage of eggs." So a supermarket egg is not a bare egg — it is a re-sealed one, kept cold. More on what to wash and what not to.
Practical answers
- US supermarket eggs: fridge, in the carton, on a shelf rather than the door, where the temperature swings least. Why the door is the warmest part.
- Eggs from a neighbor or a farm stand, unwashed: either system works, but pick one. If they go in the fridge, they stay there.
- Baking with cold eggs: take out what you need, not the carton, and keep the two-hour limit in mind.
- Leftover whites or yolks: 2 to 4 days in the fridge, or 12 months frozen once they are out of the shell. More on what freezes and what doesn't.
Separated whites and yolks are the easiest eggs to forget. Duneed, our iPhone app, lets you add them by hand with the date you want them used by, and flags them as that date gets close.
Common questions
Do eggs need to be refrigerated in the US?
Yes. US eggs are washed at the plant, which removes the cuticle, and FDA requires them to be kept at 45°F from 36 hours after laying. FSIS adds that refrigerated eggs should not be left out for more than two hours.
Why are European eggs not refrigerated?
They are not washed, so the cuticle stays on the shell and does the protecting. USDA's own description is that in most of the EU eggs "are neither washed nor refrigerated".
Can I leave refrigerated eggs out on the counter?
Not for more than two hours, in FSIS's guidance. A cold egg sweats at room temperature, and the moisture helps bacteria move through the shell.
How long do eggs last in the fridge?
3 to 5 weeks on the FSIS storage chart for raw eggs in the shell, and one week for hard-cooked eggs.
Can you freeze eggs?
Not in the shell, and not hard-cooked. Out of the shell, the federal chart gives raw egg whites and yolks 12 months in the freezer.
Should I wash farm eggs before storing them?
FSIS says no: washing can pull water and contamination through the pores. Wipe anything off dry instead.
Sources
- How We Store Our Eggs, and Why scientificdiscoveries.ars.usda.gov
- Shell Eggs from Farm to Table fsis.usda.gov
- Washing Food fsis.usda.gov
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