An eggshell looks solid enough to keep its contents fresh for months; however, shells actually contain thousands of microscopic pores that allow in air, which eventually makes the egg deteriorate. Factors that affect how long you can keep eggs include temperature, shell condition and whether they're raw or cooked. In general, raw eggs in their shell keep for three to five weeks when refrigerated.
You can safely keep your eggs at a cool room temperature for some time, but the best way to keep them fresher for a longer period of time is to put them in your refrigerator. University of California, Davis, poultry specialist Francine Bradley and professor of Animal Science Annie J. King suggest an optimum temperature of between 45 to 55 degrees Fahrenheit. They also recommend storing the eggs in the cardboard container that they came in to help cushion them from damage when you open the fridge door.
USDA-graded eggs carry what is called a Julian date. This three-digit number shows the day of the year when the egg was processed and packaged. The number 365 represents December 31, while 001 refers to January 1. From this, you can determine the age of the egg. For example, July 1 has a Julian date of 182. The carton may also display an expiration date; avoid eating eggs past their expiration date.
Once cooled, cooked eggs should be placed in a sealed container and returned to the refrigerator, no more than two hours after cooking. These eggs will keep for up to a week before turning bad, according to Michigan State University Extension. In both cases, it's safer to store the eggs in the main refrigerator shelves where the temperature is colder and more consistent than in the door. Store specialty egg products, such as pre-cooked omelets and quiches, in tightly sealed containers to prevent their going bad.
The U.S. government's Food Safety website recommends that you should not freeze raw and hard-cooked eggs that are still in their shells. Similarly, avoid freezing egg yolks, custards and homemade eggnog. However, frozen raw egg whites will keep for up to 12 months in the freezer. Some cooked egg products, such as quiche or pies, will freeze for up to two months. Always store egg products in sealed containers with air space to aid the freezing process.
If you're storing raw leftover egg whites and yolks, keep them in a sealed container in the refrigerator and use within four days. Unopened liquid egg products, such as bottled egg whites, require refrigeration and should usually be used no more than six days after storing. Once opened, keep liquid egg products refrigerated and use within three days.
Cracked eggs allow air and bacteria into the white and yolk. If an egg is cracked when you open the pack, discard the egg. If in doubt -- crack it open. A bad egg smells pretty awful and deserves to be thrown in the trash. But an egg that develops a slightly green ring around the yolk after boiling is usually nothing to worry about; the green color is a product of sulfur and iron in the egg reacting when cooking, according to Dr. Lydia Medeiros at the College of Education and Human Ecology at Ohio State University. Always use clean utensils and a clean work surface when handling eggs to prevent the spread of bacteria.
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