The Naked Scientists

The Naked Scientists Forum

Author Topic: why does eggs have expiry dates on it?  (Read 3955 times)

Offline omid

  • Neilep Level Member
  • ******
  • Posts: 1016
    • View Profile
why does eggs have expiry dates on it?
« on: 04/01/2011 15:24:38 »
OK!!! now for the 1st time in life omid noticed a egg closely,,,and omid say that it had expiry date on its pack,,,,omid's curious now,,,and omid've put the egg in a safe place,,,,now what omid is waiting is for the expiry date to pass,,,,omid have this little thought that if egg is kept longer then its expiry date a little chicken would come out of the egg,,,,now could you guys plz tell omid that shall omid expect and wait for the little chicken to come out,,or would the egg become rotten and would start stinking :-\


 

Offline CliffordK

  • Neilep Level Member
  • ******
  • Posts: 6321
  • Thanked: 3 times
  • Site Moderator
    • View Profile
why does eggs have expiry dates on it?
« Reply #1 on: 04/01/2011 20:21:39 »
omid have this little thought that if egg is kept longer then its expiry date a little chicken would come out of the egg:-\

In the USA, most "store-bought" eggs are never fertilized, so you could wait a century, and never get a "chicken" out of it.  Also, if it has ever been refrigerated, it is unlikely to grow.

"farm-fresh" eggs might be fertilized, and you will occasionally see "blood spots" in them.  You would still need to never refrigerate the eggs, and incubate them if you wish for them to hatch.

I don't have a lot of trust in the expiration dates.  If you keep your eggs in the refrigerator, they should last quite a while past the expiration date. 

Over time, the eggs may start floating in water (big end up).  I've tried to determine the reason for this, and I think that the egg white slowly evaporates.  So, the egg getting lighter is normal, and has nothing to do with bacteria growth.

If you're cooking, or making an omelet with older eggs, crack each one into a separate bowl before mixing them in with the rest of your cooking.  You can normally recognize bad eggs by a scrambled look, and a very pungent smell.  If the yolk looks fine and the egg smells ok, then go ahead and use it.

 

Offline Don_1

  • Neilep Level Member
  • ******
  • Posts: 6890
  • Thanked: 7 times
  • A stupid comment for every occasion.
    • View Profile
    • Knight Light Haulage
why does eggs have expiry dates on it?
« Reply #2 on: 05/01/2011 08:29:06 »
The Chinese have a delicacy known as '1000-year-old egg'. These are preserved duck eggs, but in effect, the eggs are usually no more than 100 days old.

 

Offline SeanB

  • Neilep Level Member
  • ******
  • Posts: 1118
  • Thanked: 3 times
    • View Profile
why does eggs have expiry dates on it?
« Reply #3 on: 06/01/2011 18:47:30 »
The reason for the expiry date is so that the supermarkets can rotate stock, as most of the times eggs are not properly kept in a cold chain from production to cooking.Often they are stacked on shelves, and often are shipped in open trucks , exposing them to high temperatures. The shell provides a lot of protection, but poor storage reduces shelf life, so the printing of expiry on all eggs, as often the eggs from one box are packed into another to replace cracked or broken items.
 

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8667
  • Thanked: 42 times
    • View Profile
why does eggs have expiry dates on it?
« Reply #4 on: 07/01/2011 12:51:18 »
Hydrogen sulphide is often describes as "smelling like rotten eggs". That implies that eggs rot.
I guess they have a sell-by date for the same reason as other perishable goods.
 

The Naked Scientists Forum

why does eggs have expiry dates on it?
« Reply #4 on: 07/01/2011 12:51:18 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums