Why are eggs in US stores refrigerated?

Just out of curiosity...I was surprised on moving to France to discover that eggs are kept on an uncooled grocery store shelf. Also, I know people who raise chickens keep the eggs in a bowl on the counter. Are eggs in the US really old by the time they get to the store? Or is this a weird health regulation? Is it actually necessary to keep eggs in the refrigerator?

  • Posted by: lloreen
  • April 29, 2012


lloreen May 1, 2012
Wow, so much information about eggs! The Food52 community is really an amazing resource. I have never been sick from eating eggs, either off the pantry shelf in France, from the fridge in the US, or straight from the hen's bottom on a farm. Maybe I have just been lucky, but I guess I will just carry on as usual and do as the Romans do...
mbergner May 1, 2012
I have been in a number of egg processing facilities for safety inspections. A number of answers below from others are abosolutely correct.
In the US we are required to "wash" eggs in order to sell to the US market. In so doing, we wash off a protective coating which otherwise protects the eggs. When washed, the shell is porous and "may" allow bacteria to enter if contaminated AFTER leaving the plant's sanitation process, so we refrigerate them. European countries don't fuss over the "pure white" look of an egg (as we do here) so they do not wash them as throughly as we do.
Eggs here are fresh, they arrive within a day or two of being laid. Eggs pick up debris and some faecal matter when being laid; free range eggs may actually be worse from a bacterial contamination point of view, as they are laid "anywhere" on the floor (with bird drippings, etc) whereas caged eggs are retained in the cage and roll out onto a conveyor; faecal matter falls through the cage onto a waste belt for mechanical transport and disposal.
Salmonella contamination from within a bird's reproductive system is another problem, but here, the bacteria are in the egg prior to the shell being laid down and hardened, most of these birds need to be sacrificed to stop the spread.
ChefOno May 1, 2012

You're absolutely correct, there are indeed viral causes of GI distress. Roughly half of food poisoning in the U.S. is caused by Norovirus.

Discussing the issue in detail is complicated because Norovirus can be transmitted directly from human to human just like the common cold and refrigeration is ineffective in controlling it. And there are dozens of other similar viruses that can be transmitted either by food or by other means.

The major problem with the term "stomach flu" isn't that it's incorrect (influenza is a respiratory illness), it's that people use it to write off food poisoning either naively believing the situation was out of their control or not wanting to accept they actually poisoned their family and friends.

ChefOno May 1, 2012

Please, pick away. It's all good.

My personal experience agrees with yours, eggs usually appear clean when they're laid. Usually, and visibly. Food safety experts tell us that, under a microscope, it's an entirely different story. Thus the regulations and procedures.

The CDC says 1 out of every 6 Americans will get sick this year from foodborne illness. Most will write the experience off as "stomach flu" (not understanding there is no such thing) but 128,000 will end up in the hospital and will 3,000 die. Everyone (except professionals) is free to roll the dice as they wish. I am only trying to convey the science as we understand it so that we can all make informed decisions.

hardlikearmour May 1, 2012
I'm just gonna pick one nit with your comment - you are correct that the term "stomach flu" is not technically correct, but there are viral causes of GI distress which in layman's terms can be called "stomach flu."
Head2Tail April 30, 2012
Just as nit-picking point of clarification, although chickens defecate and lay eggs through the same orifice (vent) the shell of the egg is often very clean upon exiting the chicken. That said, the outer surface isn't sterile but it is clean. Eggs only get feces on them if the bedding in the nest boxes (or wherever the hen lays her eggs) is dirty. If you change the bedding often, you'll have clean eggs. As for refridgeration, when we had laying hens, we didn't bother refrigerating the eggs and never became sick from eating the eggs. Then again, the eggs were so delicious they didn't sit around for long.
Truly S. May 6, 2012
here here... keep bedding clean. that is the ticket for sure. a brilliant design where you simply pull a lever or latch all is very helpful. When it comes down, put new bedding in and shovel the old out. Check in for eggs several times a day. You will know when.
ChefOno April 30, 2012

I prefer the term "understanding and respect" to the word "fear".

Unlike humans, chickens have a single posterior orifice through which they lay their eggs and defecate. Eggs and poop -- same hole. See the problem?

The natural protective coating blocks bacteria from entering the egg but pick up an egg and your hands become contaminated. Crack an egg and the contents come in contact with the outer surface of the shell. (This is the reason you're supposed to crack eggs on a flat surface instead of on the edge of a bowl, to minimize the amount of contamination.)

So, yes, eggs should be washed before cracking. And your hands afterward.

But this only covers the issue of external contamination. Contaminated feed (from chicken poop, flies, rodents, etc.) can infect the egg internally before it is laid. At room temperature, bacteria can multiply rapidly. Under optimal conditions, they can double in quantity every 20 minutes. It doesn't take long for a contaminated egg to become extremely dangerous.

alienor April 30, 2012
i get my eggs from a neighboring farm, so i don't refrigerate. but do i have to wash shells before cracking as was mentioned inlloreen's message. i have never before given it any thought....washing eggs before cracking. or is this another american fear of bacteria
Slow C. April 30, 2012
@Alienor, it depends a bit on how your friends collect the eggs and whether the eggs have been washed at all. The bottom line is that freshly lain eggs can be dirty (literally) and can have bits of this and that clinging to them. Mostly eggs from a friend's farm should be washed to get the dirt and debris off so that this stuff doesn't fall into your food. There can also be a "barnish" odor that can be removed by rinsing or a quick dip in vinegar. If there is bacteria present, a quick wash won't kill it, only cooking will. You can minimize the risk by cracking your egg on a flat surface rather than on a corner so that it is less likely the shell will break into the egg. In some cases the solmonella can be inside the egg already which is why eggs are recommended to be hard cooked to kill the bacteria. (P.S. I'm not trying to scare you! Truth be told, I don't worry about any of this when I get farm eggs, I know how the hens are raised. If we are baking, for example, my kids know not to taste test the batter unless we have used farm eggs.)
Slow C. April 29, 2012
The US is way more food safety regulated than France, eggs are only the tip of the iceburg. So, aside from US safety regulations, eggs that are refrigerated must remain refrigerated. Eggs that have not been refrigerated are perfectly fine at room temperature (in a cool pantry, for example) but fewer Americans are comfortable with that. Considering that in the US commercially sold eggs must be refrigerated from the beginning, all store bought eggs should be refrigerated. If you collect eggs from your friend's chickens then no need to worry, it's your choice.
lloreen April 29, 2012
Well I never got sick eating unchilled eggs in Europe, but I will continue to play it safe in the US.
( I was told by friends who raise their own chickens not to wash the eggs until right before cracking them so that the protective coating would remain and they would stay fresh on the counter)
ChefOno April 29, 2012

All USDA-graded eggs are required to be washed and sanitized to remove bacteria from the shell. Doing so removes the natural coating that helps protect the egg, but it is then replaced with an edible oil coating, restoring the protection. If this sounds unnecessary, consider the pathway the egg takes on its way out of the chicken's butt.

But the shell isn't the only pathway bacteria can take. The reproductive track of an infected chicken (who aren't affected by salmonella) can transfer bacteria directly to the contents, usually the yolk but the white is also at risk. This is why refrigeration is a requirement.

More than you ever wanted to know about eggs:



Voted the Best Reply!

ChrisBird April 29, 2012
I believe it is because US eggs are washed pretty thoroughly leaving the shells porous. European eggs typically aren't. So there is less opportunity for bad stuff to happen outside the fridge for European eggs.
Certainly when I moved to the USA, I was surprised by the need to refrigerate them.

I think Americas Test Kitchen did a piece on this.
ChefOno April 29, 2012

Eggs in the U.S. are often only a few days old by the time they reach the store. You can check the three-digit pack date to confirm their age.

As stated above, eggs keep longer under refrigeration. Just as important, salmonella growth is retarded by refrigeration.

razorclam April 29, 2012
In the US and Canada eggs must be refrigerated to be labeled as "Grade A". They do keep better under refrigeration.
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