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Why do eggs keep?

post #1 of 20
Thread Starter 
How come eggs stay good for weeks outside the fridge?

Anyone?
post #2 of 20
In the US you shouldnt keep eggs that are store bought outside the fridge for more than an hour, that is because when the are processed they are washed and the enzyme on the outside of the egg is washed away. If you are buying farm direct and they havent been washed they should be good for about 7-10 days at normal room temp. The outer layer of an egg, outside the shell, has an invisible layer that is an enzyme that protects it from the elements and air. Once that is gone it will begin to oxidize and rot quickly.
Taste: The sensation derived from food, as interpreted thru the tongue to brain sensory system.
Flavor: The overall impression combining taste, odor, mouthfeel and trigeminal perception.
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Taste: The sensation derived from food, as interpreted thru the tongue to brain sensory system.
Flavor: The overall impression combining taste, odor, mouthfeel and trigeminal perception.
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post #3 of 20
Chefhow is correct.

But think about it. This is a prehistoric system that in the case of birds is kept at warm temps to hatch them. If they didn't have an anti-bacterial protection of some sort, few if any eggs would incubate successfully before they rotted.

And with pasteurized eggs, they get a wax coating to seal the egg since they also wash and heat treat the egg leaving it prime for incubation of the baddies.

Phil
Palace of the Brine -- "I hear the droning in the shrine of the sea monkeys." Saltair
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Palace of the Brine -- "I hear the droning in the shrine of the sea monkeys." Saltair
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post #4 of 20
I have a neighbor who is from Wales and when she buys eggs she immediately brings them home and coats them with Vasoline and leaves them in a basket on the counter to use. She doesnt like cold eggs...
Taste: The sensation derived from food, as interpreted thru the tongue to brain sensory system.
Flavor: The overall impression combining taste, odor, mouthfeel and trigeminal perception.
Reply
Taste: The sensation derived from food, as interpreted thru the tongue to brain sensory system.
Flavor: The overall impression combining taste, odor, mouthfeel and trigeminal perception.
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post #5 of 20
all things vary.

commercial egg processing washes eggs to reduce the risk of "surface contamination"
after that, the eggs get coated with a compound to "reseal" them.

see: FDA standard/regulations for egg production.

eggs which are not processed to FDA/USDA standards, or eggs processed by companies who opt to short-cut / cheat the system should be avoided. oh, how to know? sorry, the cheaters don't label their eggs "non-conforming" - nor as recently demonstrated, do the peanut processors.

in the organic world, a fresh egg from a healthy hen will go no-questions 14 days without refrigeration. I've seen stuff saying up to 30 days is fine.

the FDA/USDA struggled with definitions. these organizations did not require proper "handling" in the period between "egg laying" and "egg processing" - effectively, if you had a hen house, and the chicken laid an egg, you could leave it there <forever> without issue because the "freshness / expiration" dating counter only started when the egg was "processed"

that has changed - but frankly I've not put all the regulatory chunks and pieces together into a coherent understanding.

the egg - or egg shell if you prefer - is a wonderful "container" designed and perfected by Mother Nature over eons of time. all that still applies but must be viewed in the light of the high volume / high density egg production du'jour.
post #6 of 20
Dilbert is correct. They are washed to rid them of any bacteria or salmonella or just plain dirt. Sometimes they are dipped in food grade wax like M&M candies are. Sometime they are dipped or sprayed with edable oil. In any event they are processed.
CHEFED
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CHEFED
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post #7 of 20
I remember in the states when eggs were kept in stores just on the shelves, as they still are here. I put them in the fridge when i get home, but they often, judging by their dates, sit around in the store for a good week. I don't know about the processing, but they do seem to keep.
In the fridge, usually they seem to keep well beyond the date. I'll break them in a bowl first to make sure they;re not gone if they;ve passed their date, and use them in baking or wherever they might be fully cooked inside something.
"Siduri said, 'Gilgamesh, where are you roaming? You will never find the eternal life that you seek...Savour your food, make each of your days a delight, ... let music and dancing fill your house, love the child who holds you by the hand and give your wife pleasure in your embrace.'"
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"Siduri said, 'Gilgamesh, where are you roaming? You will never find the eternal life that you seek...Savour your food, make each of your days a delight, ... let music and dancing fill your house, love the child who holds you by the hand and give your wife pleasure in your embrace.'"
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post #8 of 20
Can anyone, then, help dis-spell the myth that refrigerated eggs will keep indefinitely if you flip them upside down every once in a while? Something about not letting the yolk settle and touch the shell.
Sounds too good to be true. Never EVER had eggs long enough to test it.
good ol' USDA says 10 weeks. Plus a lot of blah blah blah.
post #9 of 20
Apart from all the pre-sale processing, much of the keep-ability of eggs would have to depend on the ambient temperature at which they are stored in the shelf outside of the fridge.

We live in Tasmania, Australia, where the temp in my pantry where I store my eggs in the carton in the dark would rarely exceed 10 deg C for much of the year. I've kept eggs in there for 3 weeks with no probs. In summer, I use them before the week is up, or surrender and keep in the fridge if its particularly warm in the house.

When we lived in Darwin (tropics) where the ambient temp was never much below 25 deg C for much of the year - they lived in the fridge from day 1. But I don't like having them in the fridge. They pick up any lingering odours (as when you store them with truffles to get them that flavour on purpose). If they go into the fridge, they sit in the carton to avoid much of that - not in the silly egg rack :) I use that for holding jars of anchovies and horseradish cream, capers, mustards, etc.
 Don't handicap your children by making their lives easy.
Robert A. Heinlein

 
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 Don't handicap your children by making their lives easy.
Robert A. Heinlein

 
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post #10 of 20
EGGS dehydrate a little bit more every day(that is lose inner moisture). In fact one of ways to tell a fresh egg is drop it in water and see how fast it sinks because as it looses moisture the air pocket in the egg gets larger and makes it more buoyant, They will however last for monthes in fridge but quality goes down daily..:bounce:
CHEFED
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CHEFED
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post #11 of 20
Eggs are rarely refrigerated in Japan. The dates on the package are laying date and "use-by" date, which are pretty close together -- 2 weeks, I think. Most supermarkets have them someplace that's not actually hot but not in any sense refrigerated.

I've heard quite the contrary. Between the fat part of the egg and the yolk, there is a little string that holds the yolk in place. Eggs should be stored pointy-part down, so the yolk remains suspended. This is also why there is an air chamber below the shell of the fat part, and this is the bit you pierce when you make hard-boiled eggs. My understanding is that if you leave an egg pointy-side up too long, the yolk settles on the bottom; from what I've read, however, this isn't a safety problem so much as a texture and taste one -- the yolk won't be as good if it's sitting squashed like this.
post #12 of 20
Technically speaking, if the laying hen is healthy (has no infections) then the egg material inside the shell coming out of the hen is sterile (no bacteria).

An egg is one cell: yolk is the nucleus which has a membrane around it and the white is the cytoplasm that is enclosed in a membrane as well (it it stuck to the inner side of the shell and goes around the yolk). Egg whites contain many different types of protein and antibiotic type chemicals to stop bacteria from propagating (if they would enter the egg through a shell fracture). Many proteins in egg white react with metallic ions that also is a method to prevent bacterial propagation by binding essential minerals.
In a funny way this explains the green/black ring around the yolk when eggs are boiled because the escaping minerals from the yolk get trapped by the egg white proteins as they come out the yolk creating a coloured sphere (ring). Also this explains why egg whites beat up nice in copper bowls, the ions in the bowls has a particular affinity to egg white proteins.

last the egg yolk is indeed suspended in the middle of the white. The egg white membrane is continuous from the shell and around the yolk. When the hen lays the egg, she turns the egg on it's side always in the same direction. This twists the membrane together with egg white proteins creating 2 twisted strings at opposite ends maintaining the yolk in place (similar to someone trapped in a twirled hammac).

In Europe, refrigeration is not required for eggs but In Canada it is mandatory as a precautionary measure.

Luc H.
I eat science everyday, do you?
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I eat science everyday, do you?
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post #13 of 20
Well,it was a story I heard in Alaska. "they'll keep for 3 months if we just flip them"...
Maybe it was necessity that made it true.
People did all sorts of messed up stuff.
post #14 of 20
It's funny those little differences. I live in Spain and don't need to refrigerate my eggs, of course. I'm not sure I really get why they treat them with chemicals in the US in the first place if it creates problems. Sure, sometimes I get an egg with a little chicken feather stuck to a little streak of chicken poop... but I just rinse it off right before using. :)

They DO come out of chickens, after all. So it seems natural to me! I'm glad my eggs aren't soaked in chemicals.

-Karen
post #15 of 20
is the lack of this outer layer also why eggs tend to absorb odors if they are not kept in the carton?
post #16 of 20
A little clarification here: The outside shell of an egg is coated with a waxy substance called: cuticle (aka bloom).
This substance acts as a lubricant to help the hen during laying. In North America, each commercial egg is washed and sanitized. This removes this waxy substance.
Another role for the cuticle is to minimize moisture loss since the shell is porous to water vapours and air. An egg that lost moisture shrinks inside, the air sac gets bigger because of the vacuum created hence it will float in water indicating it is not fresh.

A scientific article that investigated this fact: http://ps.fass.org/cgi/reprint/77/10/1522.pdf

Some studies have investigated the antimicrobial effects of the egg cuticle and it does appear it contains some antimicrobial enzymes (ex lysozyme). If the shell is intact though (no cracks) these exterior substances are useless. Important to note that Lysozyme is also found in egg white were it is more usefull at protecting the egg if microbes are present.

Hope this helps
Luc H.
I eat science everyday, do you?
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I eat science everyday, do you?
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post #17 of 20
I thought in the US after washing the eggs were sprayed with some kind of wax or lacquer or something, making them as oxygen-impervious as when the cuticle was intact. No?
post #18 of 20
>>No?

yes.
post #19 of 20
I just came back to Canada after being in the UK for a year. They don't keep their eggs in the fridge at all, so now it just seems wrong to be putting them in there. And while there's probably no truth to this, I would swear to you that the eggs smell better over there!
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Want to see what I'm getting up to at college and in my spare time? Check out my blog or feel free to recommend one you think I might like!
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post #20 of 20
No truth in it? I KNOW the eggs in Japan, which are rarely refrigerated, smell and taste better than in the US.
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