How to Tell If Eggs Are Bad

It's easy to tell when most foods have gone bad: They'll let you know with a distinct smell or look. But what about eggs? There's not much you can tell by simply looking at or smelling one, especially if the shell hasn't been cracked or punctured. So how can you tell when eggs are bad? When in doubt, should you throw them out? Not yet! Before you head to the compost bin, here are a few ways to check if your eggs are still safe to eat.

Check the Packing Date, Not the Expiration or Sell-By Dates

The most reliable date stamped on your egg carton is not the expiration or sell-by date, but the packing date. The expiration date is a general guideline about freshness, and the sell-by date is a tool for stores to use in order to gauge how long a product should sit on the shelf. Neither will tell you exactly how old your eggs are.

The packing date, on the other hand, is the exact day your eggs were put into the carton. Sometimes it's not easy to identify because it's indicated using the Julian date calendar—a system where days of the year are counted chronologically starting with 1 for January 1 and continuing through 365 for December 31. To find the packing date, look for a three-digit code near the "use-by," "sell-by" or "exp" date. If stored properly, your eggs should be fine to eat within four to five weeks of the pack date and two to three weeks after the expiration date, according to United Egg Producers. If you're not into deciphering dates and codes on cartons, the Institute of Agriculture and Natural Resources at the University of Nebraska-Lincoln recommends eating your eggs within three to five weeks of the day you purchased them.

Do a Float Test

If you can't find the Julian date or it's smeared beyond readability, a float test may be the way to go. Eggshells are porous (air can easily penetrate them), which means the older the egg, the more air inside it. After enough time has passed, the egg will have enough air inside to make it float.

To conduct a float test, fill a bowl or cup with water (it should be big enough to fully submerge your egg). Gently place your egg inside and see if it sinks or floats. If it floats, it's old and you may want to toss it. But, the USDA's Food Safety and Inspection Service says an old egg "may be perfectly safe to use. Crack the egg into a bowl and examine it for an off-odor or unusual appearance before deciding to use or discard it. A spoiled egg will have an unpleasant odor when you break open the shell, either when raw or cooked."

If the egg sinks and stands up, then it's not very fresh but still safe to eat. If it sinks and falls to its side, then the egg is at its prime.

Can I Tell If an Egg Is Bad by Shaking It?

You can also perform a shake test to see if your eggs are bad. Hold an egg by your ear and shake it. If you hear nothing, then many say your egg is OK, based on anecdotal evidence. If you hear liquid sloshing around, it means the yolk and/or white have deteriorated and are no longer fresh and firm but rather old and watery. However, FSIS does not endorse this test for freshness, like they do the float test. Your best bet is the float test or, even easier, cracking the egg open.

Crack It Open

The most accurate way of testing whether your eggs have gone bad is to crack them open. If the yolk or white has any discoloration, the egg is no good. Discoloration is an indication of bacterial growth. If your eggs look good but have an off or sulfuric smell to them, they are bad. Compost them.

According to food writer and Culinary Institute of America-trained cook Sean Kenniff, "A fresh egg should have a bright yellow or orange yolk that is more rounded than flat. The yolk should sit high on the inner albumen (that's the thicker part of the white directly surrounding the yolk), and the inner albumen itself should not spread too much from the yolk and be relatively thick. The thinner outer albumen should not spread too far from the inner albumen. And there should be no off smells or colors."

What If I Eat a Bad Egg?

In the unlikely event that you happen to eat a bad egg, you may be at risk for foodborne illnesses such as salmonella. Food poisoning may cause you to have a fever, abdominal pain, diarrhea and vomiting. For most people, symptoms go away within a few days; however, serious illness and hospitalization can follow. Best to avoid eating a bad egg if possible.

How to Properly Store Eggs

Eggs have a long shelf life as long as they're refrigerated properly. Instead of storing your eggs on the inside of the fridge door, place them in the coldest part of your fridge, which is usually the middle or bottom shelf. The door is actually the warmest part of your fridge because it gets exposed to ambient temperature every time you open it.

Keep your eggs in the carton. The carton protects and insulates the eggs from breaking and absorbing excess air. For your eggs to last as long as possible, FSIS recommends keeping the temperature of your fridge at 45°F and lower. And don't leave your eggs out! According to FSIS, "Discard all perishable foods such as meat, poultry, eggs and casseroles, left at room temperature longer than 2 hours; 1 hour in temperatures above 90°F."

The Bottom Line

As long as they've been stored properly, eggs can keep for four to five weeks after they've been packed. Make sure to store your eggs in the coldest part of your fridge and in the carton they came in. If you're ever in doubt, perform one of the tests (float it or crack it, don't shake it) to determine whether your eggs should be used or tossed.