Can You Get Sick From Eating Old Eggs? | The Real Risk

You crack an egg into a hot pan and pause. The carton’s sell-by date was last week. The egg looks fine — no off-color, no smell. Surely one day past a printed date won’t hurt anyone, right?

That instinct is common, and often it works out just fine. But the relationship between an egg’s age and its safety isn’t straightforward. An egg can be past its date yet generally considered safe, or it can look and smell normal but still carry bacteria that make you sick. This article walks through what actually makes old eggs risky, how to tell the difference between spoiled and contaminated, and which tests you can trust in your own kitchen.

What Actually Makes An Old Egg Unsafe

There are two separate ways an old egg can make you sick, and confusing them leads to most of the uncertainty around egg safety. One is spoilage; the other is contamination.

Spoilage happens as an egg ages. The yolk thins, the white becomes watery, and the air cell inside the shell grows larger. Eventually, bacteria that were present on the shell or inside the egg multiply enough to cause visible changes and a sulfur smell. A spoiled egg is usually obvious once cracked open.

Contamination is a different problem. Fresh eggs can carry Salmonella bacteria even when they look and smell perfect. Per the FDA, fresh eggs with clean, uncracked shells may still contain these bacteria. As eggs age, the risk doesn’t always increase predictably — but damaged shells, improper refrigeration, and extended storage all raise the odds that Salmonella will multiply to levels that cause illness.

The Two Risk Paths

The distinction matters because spoilage is preventable by simple inspection, while contamination requires different precautions. You cannot reliably smell or see Salmonella bacteria. This is why food safety agencies emphasize cooking and storage over freshness tests.

Why The Date Label Causes Confusion

The printed date on an egg carton is not an expiration date in the way most people assume. A “sell-by” date tells the store how long to display the eggs — no more than 30 days after packing, per USDA guidelines. It is not a safety cutoff.

Eggs can remain safe to eat for several weeks beyond that date, provided they were refrigerated the whole time and the shells remain intact. The confusion stems from assuming the carton date predicts spoilage, when in fact it predicts peak quality for the retailer. Many people throw away perfectly good eggs because of a date that was never meant to signal danger.

The Julian date, a three-digit number printed on the carton (001 to 365, representing the day of the year the eggs were packed), is a more useful freshness marker. Healthline suggests checking both the sell-by date and the Julian date as a first step in determining whether your eggs are still fresh.

• Spoiled eggs: Easy to identify by smell or appearance once cracked. Cause digestive discomfort that is usually short-lived. Older eggs with larger air cells float in water.
• Contaminated eggs: May look and smell completely normal. Carry Salmonella bacteria that require thorough cooking to kill. Symptoms show up 6 to 48 hours after eating.
• Freshness isn’t safety: A very fresh egg can still be contaminated. An older egg that passes the sniff test can still be safe if handled properly.
• Refrigeration matters more than age: Eggs stored at 40°F or below age slowly. Eggs left at room temperature age as much in one day as they do in one week in the fridge.
• Shell integrity is critical: A cracked shell opens a direct path for bacteria. Even a hairline crack you can’t see increases risk significantly.

How To Tell If An Egg Is Safe To Eat

No single test gives you a guarantee, but a combination of checks can help you make an informed call. The sniff test is the most reliable: a fresh egg has virtually no odor, while a bad egg gives off a distinct sulfur or rotten smell. Everyday Health’s comparison of spoiled vs contaminated eggs notes that bacterial contamination may go undetected by smell alone.

The float test is widely known and easy to do. Place the egg in a bowl of cold water. A fresh egg sinks and lies flat on its side. An older egg tilts upright or floats entirely, because the air cell inside the shell has grown larger as moisture evaporated through the porous shell. Floating eggs are older and should be discarded.

A few other checks help. The shake test: hold the egg near your ear and shake gently. Fresh eggs make little to no sound. Older eggs may slosh as the watery white moves inside the shell. You can also hold the egg up to a bright flashlight or phone light — a process called candling — to look for cracks, blood spots, or an unusually large air cell.

None of these tests detect Salmonella contamination. A floating egg that passes the sniff test is still fine to eat after cooking, but a fresh-looking, fresh-smelling egg could still carry bacteria. The safest approach is to treat all eggs as potentially contaminated and cook them thoroughly.

The Key Factors That Reduce Your Risk

FoodSafety.gov makes it clear that proper egg handling is the most effective way to reduce the risk of illness. Eggs should be refrigerated at 40°F or below as soon as you bring them home. Never leave eggs at room temperature for more than two hours.

Cooking is the critical step. Salmonella bacteria are killed at an internal temperature of 160°F, which means yolks should be firm, not runny. Scrambled eggs should be cooked until no visible liquid egg remains. Casseroles and dishes containing eggs should reach 160°F throughout.

The food safety eggs page emphasizes that even properly cooked eggs can make you sick if you handle them unsafely after cooking. Avoid leaving cooked egg dishes at room temperature for more than two hours, and refrigerate leftovers promptly.

1. Keep eggs refrigerated. Consistent cold storage slows bacterial growth significantly. Don’t store eggs in the refrigerator door, where temperatures fluctuate more than on the main shelves.
2. Cook eggs thoroughly. Firm yolks and fully set whites are the target. Sunny-side-up or soft-boiled eggs carry higher risk because the yolk may not reach 160°F.
3. Check shells before cracking. Discard any egg with a visible crack or leak. Wipe the shell clean before cracking to avoid transferring bacteria to the egg inside.
4. Wash hands and surfaces. Raw egg residue on countertops, utensils, or hands can cross-contaminate other foods. Use hot soapy water after handling raw eggs.
5. Don’t rely solely on dates. Sell-by dates indicate store display limits, not safety cutoffs. Use the float test and sniff test together with good storage practices.

What Happens If You Eat A Bad Egg

If you eat a spoiled egg, the most likely result is a digestive upset. Everyday Health notes that mild discomfort from eating a bad egg can include a stomach ache or nausea that is usually short-lived. The body tends to reject spoiled food quickly, and many people experience these symptoms without needing medical attention.

A Salmonella infection is a different situation. Symptoms typically show up between 6 and 48 hours after eating the contaminated egg. Diarrhea, stomach cramps, fever, and vomiting are common. Most healthy adults recover within a few days without treatment, but the infection can be more serious in young children, older adults, pregnant women, and people with weakened immune systems.

Severe symptoms — bloody diarrhea, a fever above 102°F, signs of dehydration, or symptoms lasting more than three days — warrant a call to a healthcare provider. In rare cases, Salmonella can spread from the intestines to the bloodstream, requiring hospitalization and antibiotics.

The Bottom Line

A past-its-date egg is not automatically dangerous. The real risk comes from two separate problems: spoilage, which you can usually detect by smell or appearance, and Salmonella contamination, which you cannot. Refrigeration, thorough cooking, and checking shells for cracks are your most reliable protections. The float test and sniff test are useful indicators of freshness but cannot confirm whether bacteria are present.

If you’ve eaten an old egg and develop severe or prolonged symptoms — bloody diarrhea, high fever, or signs of dehydration — contact your healthcare provider, who can determine whether testing or treatment is needed based on your symptoms and health history.