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What to Know About Eggs Going Bad

Medically Reviewed by Dan Brennan, MD on October 25, 2021

Chances are you have a carton of eggs in your refrigerator. Even though it has an expiration date stamped on the side, you may wonder if your eggs go bad sooner or even last longer. How can you tell if your eggs are going bad?

About Eggs Going Bad

As eggs age, the air cell inside grows larger and larger. Many people say that you can tell if an egg is bad if you place it in water and it floats. While this is a good way to test the age of an egg, floating doesn’t necessarily mean it’s going bad.

If you do test an egg by placing it in water, you can still crack it open to see if it’s a bad egg. When you crack it open, look for other signs of discoloration or a sour smell. A fresh egg doesn’t have a smell, but an egg that is going bad smells like sulfur. If you smell something, chances are, the egg is no longer good.

Understanding egg color. You’re used to seeing a yellow yolk and a clear egg white. There are variations of color that are safe and others that are not:

  • Red spot on the yolk – This is also called a blood spot, and it happens at the time a chicken ovulates, producing the yolk. A red spot happens when a blood vessel around the yolk bursts. Eggs with a red spot are safe for consumption.
  • Cloudy egg white – Cloudiness is actually an indication that your egg is very fresh. High levels of carbon dioxide cause cloudiness when the egg is laid. With time, cloudiness clears. These eggs are safe to eat.
  • White strings in the egg white – This is also called chalazae. It keeps the egg yolk in place on the egg white. More prominent white strings indicate that you have a very fresh egg. White strings do not need to be removed before cooking.
  • Brighter or darker yolk – What a hen eats affects the color of the egg yolk she lays. If hens are fed wheat and barley, the yolk is paler. If a hen is fed green plants and corn, the yolk is darker. Hens that are fed wheat and barley produce eggs with lighter color yolks. Hens that are fed green plants, corn and alfalfa produce eggs with darker color yolks. The color of the yolk does not indicate freshness or the health of the mother hen.
  • Green ring around cooked yolk – If you cook an egg in the shell by hard-boiling it, the yolk may turn green from overcooking. Sulfur and iron react to the heat, turning the yolk slightly green. The eggs are still safe to eat. ‌
  • Egg white that isn’t white – If the egg white isn’t clear or cloudy white, it may be bad. If your egg white has a green or iridescent look, it may have harmful bacteria. It may not be safe for consumption. If you notice that the color is off, smell your egg. It’s always good to err on the side of caution and throw out eggs that may be bad.

Risks of Eating Bad Eggs

Bacteria.Salmonella is common in eggs, whether they are good or bad. However, salmonella is cooked out of eggs with heat. As eggs go bad, they develop other types of bacteria like E. Coli that lead to severe illness. 

If an egg is bad, symptoms of illness appear within six to 48 hours and may include:

  • Diarrhea
  • Stomach pain and cramps
  • Fever‌
  • Vomiting

Symptoms will typically show up between six and 48 hours after eating a contaminated egg and can last between 4 and 7 days. In most cases, the symptoms go away on their own.

Keeping Eggs Fresh

Knowing how to maintain your eggs can help you prevent them from going bad. Keep these tips in mind when you purchase eggs:

  • ‌Open the carton before you buy to check for eggs that are dirty or have cracks. Don’t buy eggs that have visible dirt, feces, or cracks.
  • ‌Don’t let your eggs sit too long before refrigerating them.
  • ‌ Store eggs in their carton to ensure they don’t break. The carton also helps your eggs keep moisture. It also keeps your eggs from taking in the other odors in your fridge.
  • ‌Place eggs on the back of the shelf to ensure a more stable temperature. If they are close to the fridge door that opens and closes frequently, it may affect their temperature.
  • ‌If you take eggs out and don’t use them, refrigerate again within 2 hours. If your eggs stay out longer than that, throw them out.
  • ‌If your carton doesn’t have an expiration date, mark down when you bought them. As long as they're stored correctly, eggs are usually good for up to 6 weeks from the date of purchase.

Show Sources

SOURCES:

Centers for Disease Control and Prevention: “Salmonella and Eggs.”

Institute of Agriculture and Natural Resources: "Cracking the Date Code on Egg Cartons."

Mayo Clinic: “Egg Allergy.”

U.S. Food & Drug Administration: “What You Need to Know About Egg Safety.”

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