How to Tell if an Egg Is Good or Bad?

Medically Reviewed on 8/12/2022

Check the expiration date

If you're wondering how to tell if an egg is bad, there are several methods you can use. You can tell if an egg is good or bad by inspecting it, sniffing it, doing a float test, and conducting other tests.
If you're wondering how to tell if an egg is bad, there are several methods you can use. You can tell if an egg is good or bad by inspecting it, sniffing it, doing a float test, and conducting other tests.

If you're wondering how to tell if an egg is bad, there are several methods you can use. The easiest is checking the expiration date, but eggs are often still good weeks after the date printed on the carton.

More reliable methods include using your senses to inspect, smell, and shake the egg. You can also place it into a glass of water and see if it floats. These are easy methods you can do at home.

Store-bought cartons of eggs have expiration dates or sell-by dates printed on them. The expiration date has to be within 30 days of the pack date to ensure that consumers are buying fresh eggs.

Some cartons also have a Julian date to show when they were packed. These dates don't use the usual formatting with the month, date, and year. Instead, the Julian date is a three-digit number without slashes or other punctuation, where 001 represents January 1 and 365 (or 366 on a leap year) represents December 31.

In general, eggs are good for 5 weeks after the pack date as long as you keep them in the refrigerator. If there's no pack date, your eggs should be good for 3 weeks after you bought them. If eggs are left on the counter overnight or aren't refrigerated for long periods of time, there's a chance that bacteria has started growing, and they should be discarded.

After the expiration date, the quality of the eggs might decline, but they can still be safe to eat for several weeks. Before throwing them out, use another method to tell if an egg is good or bad.

Inspect the outside

Never buy cracked eggs from the store. Bacteria can enter the egg through cracks in the shell and make you sick. If eggs crack on the way home from the store, crack them into a clean container and store them in the refrigerator for up to 2 days.

Eggshells can come in a variety of colors, including white, brown, green, and blue. As long as the shell doesn't change color, it's safe to eat eggs of any color. However, if the shell doesn't look or feel clean, then it should be thrown away. For example, a slimy feeling can be a sign of bacterial growth.

Mold can grow on the outside of eggs if they're washed incorrectly or stored in humid environments. The biggest sign of mold growth is powdery spots on the eggshell that come off when wiped.

Look at the inside

The easiest way to inspect the inside of an egg is by cracking it on a white plate. Look for discoloration of the egg whites or yolk. Colors like green, pink, and blue mean there is bacterial growth and the egg isn't safe to eat.

Yolk colors can vary slightly but should always be yellow when raw. Hens that are fed wheat and barley lay eggs with lighter yolks. Hens that are fed corn and leafy greens produce darker yolks. The yolk color does not change the egg quality or flavor.

Although it may be unappealing, a small red spot next to the yolk is normal. It happens when a small blood vessel around the yolk pops. You can scoop out the blood spot and discard it, but it's not harmful to eat.

Cloudy egg whites are also okay. It actually means your eggs are fresh. There is naturally occurring carbon dioxide inside the egg when it's laid, which makes the whites look cloudy. Over time, the carbon dioxide is released through the pores of the eggshell, and the egg whites become more clear.

A green or gray ring around the yolk of a hard-boiled egg is a sign of overcooking, not bacteria growth. These eggs are safe to eat.

Conduct a sniff test

Doing a sniff test with your eggs is a foolproof way to determine if they've gone bad. Fresh eggs don't smell like anything, but bad eggs have a distinct odor. If your eggs smell like sulfur, they've started rotting and you shouldn't eat them.

As eggs age, their proteins break down and produce hydrogen sulfide. This is a toxic chemical that gives off a noticeable smell in both cooked and raw eggs that have gone bad. If you smell sulfur, throw away your eggs, clean any dishes they touched, and wash your hands.

Shake it

Hold an egg up to your ear and shake it. If you hear or feel liquid moving, that means the egg is old and its yolk has become watery. This doesn't always mean the egg is rotten, though. Crack it open and do a visual inspection or sniff test to double-check whether it's safe.

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Do a float test

Doing a float test is an easy way to tell if your eggs are still good — and you don't have to crack them open to do it. Simply place an egg in a glass of cold water, making sure there's enough water for the egg to be completely submerged. If it sinks, it's good to eat. If it floats, then the egg is old and likely unsafe to eat.

This test works because the yolk and egg white decompose over time, producing gas that escapes through tiny pores in the eggshell. This process makes the egg less dense than the water around it. And when something is less dense than water, it will float. 

Eggs that haven't started rotting are denser than water, which is why they sink and lay flat on their side. An egg that sinks but stands on its end is older but likely still safe to eat.

When doing the egg float test, it's important to use unsalted water. Salt increases the density of the water, so both good and bad eggs will float. It's also better to use cold water instead of room temperature or hot water because the temperature can affect water density.

The egg float test works with any type of eggs, including chicken, duck, and quail eggs.

How to store eggs

Storing your eggs correctly will keep them safe to eat and can extend their shelf life. After you buy eggs, put them in the refrigerator as soon as possible. They should be stored at or below 40 degrees Fahrenheit.

Keep eggs in their original carton. Not only does this keep them from being bumped and broken, but the carton also has the expiration date on it.

You should keep hard-boiled eggs in the refrigerator and eat them within 1 week of cooking them.

If your eggs are about to go bad, you can freeze them. Frozen eggs can be kept for up to a year. Just don't freeze them in their shells. Instead: 

  1. Crack the eggs and beat the yolks and whites together. 
  2. Store the eggs in a freezer-safe container or bag. 
  3. When it's time to use them, thaw the eggs in the refrigerator overnight. Never thaw them on the counter.

What happens if you eat a bad egg?

Salmonella is the main concern with bad eggs. It's a bacteria that can be found both on the outside of eggs and inside of them. Salmonella symptoms begin between 6 hours and 6 days after eating affected food and include:

Most people recover within a week and don't require medical treatment or hospitalization. Children under 5 years and adults 65 years and older are more likely to get seriously ill. If you're worried about your health or that of a loved one, talk with your doctor.

Salmonella is rarely spread from person to person. If you think you're sick, you don't have to worry about spreading it to others. Just remember to wash your hands thoroughly after using the restroom and before handling food.

It's easy to avoid getting Salmonella from eggs. The bacteria are killed at high temperatures, which is why it's recommended to cook eggs until both the yolk and white are firm. Avoid eating batter or dough made with raw eggs.

After working with raw eggs, use soap and water to wash your hands. Wash or clean any items that touched raw eggs, including: 

  • Countertops
  • Pots and pans
  • Utensils
  • Bowls
  • Cutting boards 

You can also choose to buy pasteurized eggs, which have been heated in warm water to kill bacteria. This lessens your chances of being infected with Salmonella or other food-borne bacteria.

Can you eat expired eggs?

Yes, you can eat expired eggs. They need to be stored properly in the fridge and pass inspection, but it is generally safe to eat eggs past their expiration date.

Before eating the eggs, check for any discoloration, see if they float in water, and give them a sniff. Discolored yolks or whites, slimy eggshells, and any hint of sulfur mean the eggs should not be eaten. It is best to throw them away and buy a new carton.

If you want to be extra careful when using expired eggs, use them in fully cooked items like quiches, casseroles, or baked goods to reduce your risk of food-borne illness.

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Medically Reviewed on 8/12/2022
References
SOURCES:

AskUSDA, U.S. Department of Agriculture: "How do commercial plants pasteurize an egg?"

Centers for Disease Control and Prevention: "Salmonella and Eggs."

Cleveland Clinic: "Salmonella."

Egg Safety Center: "Six things to know about the inside of an egg," "Top five egg safety questions."

The Incredible Egg: "Egg Handling and Care Tips," "Frequently Asked Questions About Eggs," "How to Freeze Eggs."

Science Notes: "Why Bad Eggs Float and Good Eggs Sink."

University of Hawai'i at Manoa, Exploring Our Fluid Earth: "Density, Temperature, and Salinity."

U.S. Food and Drug Administration: "What You Need to Know About Egg Safety."