Egg-cellent tips for egg lovers
Q. Can you tell me how long eggs are good for after the best-buy date on the carton has expired? Are they safe to use in recipes or not?
L.D., Walnut Creek, Calif.
A. Eggs that have a U.S. Department of Agriculture grading need to display the day of the year (from 1 to 365) on which the eggs were packed. Most egg cartons will also display an expiration date, month and day after which they can no longer be sold but are still safe to eat. Assuming they have been under constant refrigeration, you have about four to five weeks after the pack date during which the eggs are considered fresh and safe. The expiration date will pass during this period. A good rule of thumb is to use fresh eggs within three to five weeks after purchase.
As time passes the eggs gradually lose some of their qualities. In a fresh egg, the yolk is compact and stands high, and the white stays close to the yolk. As the weeks pass, the yolk and the egg white begin to spread, and the yolk sack becomes more fragile. Anyone who eats their eggs sunny side up or over easy will notice that it doesn't take much to rupture the yolk of an older egg. Such changes result from subtle changes in the egg albumin, the protein in the egg, but this does not have a significant impact on the egg's nutritional value. Over time, though, the changes can affect how an egg performs in certain recipes.
Use the freshest eggs for poaching or frying, as older ones will be more runny. If you want your egg to be whipped for volume, such as a meringue, or in a cake, it's OK to use a middle-aged egg (about 10 days old). Older eggs will perform fine if they are going to be used in a batter. If you are going to be making hard-boiled eggs, older ones are preferred as it is easier to take the shell off an older egg than a fresh one.
If the expiration date is long gone and you have concerns, it is always best to discard the eggs. If you do end up using eggs near or just after their time is up, be sure to cook them well. That is always the best way at eliminating any bacteria in the off chance that some might have taken up residence. The USDA has a booklet on how to buy eggs at tinyurl.com/6kqc34, and there is more detailed information about safety at eggsafety.org.