According to the U.S. Dept. of Agriculture (USDA):
Many eggs reach stores only a few days after the hen lays them. Egg cartons with the USDA grade shield on them, indicating they came from a USDA-inspected plant, must display the 'pack date' (the day that the eggs were washed, graded, and placed in the carton). The number is a three-digit code that represents the consecutive day of the year (the 'Julian Date') starting with January 1 as 001 and ending with December 31 as 365.
Sell By Date - Though not required, most egg cartons also contain a "sell by" date beyond which they should not be sold. In USDA-inspected plants (indicated by the USDA shield on the package), this date can't exceed 30 days beyond the pack date which is within USDA regulations.
Always purchase eggs before their "sell by" date. Information from the Georgia Egg Commission:
Julian Date: Starting with January 1 as number 1 and ending with December 31 as 365, these numbers represent the consecutive days of the year. This numbering system is sometimes used on egg cartons to denote the day the eggs are packed. Fresh shell eggs can be stored in their cartons in the refrigerator for 4 to 5 weeks beyond this date with insignificant quality loss.
Expiration Date: The "sell by" or "best if used by" or "exp (date)" are all expressions used by the industry in various states, and are used by the retailer to assure you of freshness. The egg will continue to be fresh for at least another 2-3 weeks if it has been refrigerated from the time packed until used at 45 degrees F. or lower. As the egg ages, it does lose some of its qualities, so if you were baking a cake or whipping meringue, your cake might not rise as high as expected, and you might not get the volume of meringue you would expect, so for baking purposes it is better to use a fresher egg.
How long are eggs good after the sell date?
Refrigerated raw shell eggs will keep without significant quality loss for about 4 to 5 weeks beyond the sell date or about 3 weeks after you bring them home.
A general rule to follow is that any egg that looks or smells odd should NOT be used. Just crack each egg in a small bowl, smell it - your nose will tell you!
How to test if an egg is fresh:
Fill a deep bowl with water and carefully lower the egg into the water. A very fresh egg will immediately sink to the bottom and lie flat on its side. This is because the air cell within the egg is very
small. The egg should also fee quite heavy.
As the egg starts to lose it freshness and more air enters the egg, it will begin to float and stand upright. The smaller end will lie on the bottom of the bowl, while the broader end will point towards the surface. The egg will still be good enough to consume.
However, if the egg fully floats in the water and does not touch the bottom of the bowl at all, it should be discarded. as it will most likely be bad.
Test the eggs freshness by breaking the egg onto a flat plate, not into a bowl. The yolk of a very fresh egg will have a round and compact appearance and it will sit positioned quite high up in the middle of the egg. The white that surrounds it will be thick and stays close to the yolk.
A less fresh egg will contain a flatter yolk, that may bread easily and a thinner white that spreads quite far over the plate.
How to store eggs?
The USDA recommends storing eggs in a refrigerator at about 40 degrees F, mainly to reduce the chances that any bacteria on the shell will multiply and cause a risk of illness.
Buy refrigerated eggs and store them in the refrigerator as soon as your get home. However, even under refrigeration, eggs slowly lose carbon dioxide, which enlarges the size of the air cell and causes the yolk to flatten and the white to spread.
Storing Fresh Egg - Refrigerated raw shell eggs will keep without significant quality loss for about 4 to 5 weeks beyond the "sell by" date or about 3 weeks after you bring them home.
Fresh egg whites - 2 to 4 days
Fresh egg yolks (unbroken and covered with water) - 2 to 4 days
Hard-cooked (hard boiled) eggs - 1 week
Deviled eggs - 2 to 3 days
Leftover egg dishes - 3 to 4 days
Whole eggs (in the shell) cannot be frozen as the eggs will burst. Store in an airtight freezer container. The recommended length of freezer storage for frozen eggs is 9 to 12 months.
Whole eggs - You can freeze an entire egg by beating it (as if you were making scrambled eggs) and then storing it in an airtight freezer container.
Egg yolks - Separate eggs. Stir yolks with a fork to break them. Add two teaspoons sugar or one teaspoon salt for each cup of egg yolks. Store in an airtight freezer container.
Egg whites - Strain whites through a sieve. Freeze without stirring. Do not add sugar or salt. Store in an airtight freezer container.