Eggs are packed with protein and minerals—plus they're not cheap.12 So it can be really frustrating to open your egg carton to discover that one or multiple shells inside have hairline cracks. Are these slightly-damaged eggs safe to eat, or could they make you sick?

Experts, dietitians, and food safety experts weigh in on when it's safe to eat a cracked egg, and when you might be better off throwing it away.

The Quick Answer

Determining whether a cracked egg is safe to eat depends on how and when the break occurred, Vanessa Coffman, PhD, food safety expert and director of the Alliance to Stop Foodborne Illness, told Health.

If the crack happened before you brought your eggs home—meaning you spotted it at the grocery store—it’s best to toss the cracked egg in the garbage, or refrain from purchasing that carton of eggs at all, Coffman said. Harmful bacteria may have already entered through the broken shell.

If the egg cracked while you were transporting it home or while you were handling it, you can use it. But do so immediately, and make sure the egg is cooked fully, she said.

An important caveat is if the egg is cracked and leaking, said Elisa Maloberti, manager of special projects and food safety at The American Egg Board. In those cases, discard the egg right away.

If the cracked egg is not leaking, that indicates that the membrane located just beneath the shell is still intact, she told Health. These eggs are generally safe to eat, but again, need to be consumed right away.

What Causes Eggs to Crack (And Why It Matters)

Only clean, intact eggs make it through the production process, but breakage can occur once the eggs have been packed and shipped, Maloberti said.

"Even though care is taken to package eggs in protective cartons, they are fragile and can easily crack during transport or while being stocked in the grocery store," added Amy Woodman, RD, a registered dietitian with Farmington Valley Nutrition and Wellness. "It is important to check your eggs [...] to make sure there are no cracked shells."

When an egg has a crack, bacteria can enter through the shell and contaminate it.3

"The main food safety concern with cracked eggs is Salmonella, a harmful bacteria that can cause serious illness especially in young children, older adults, pregnant individuals, and those with weakened immune systems," Coffman explained.

Salmonella is a very common cause of food poisoning in the U.S.—it causes about 1.35 million infections and 26,500 hospitalizations annually.45

When Is It Safe to Eat a Cracked Egg—And When Isn’t It?

When stored properly in your refrigerator, eggs are safe to eat for an extended period of time, said Maloberti. But cracks of any kind can call that into question.

Whether you notice cracks in the carton or while you're cooking, here are the guidelines you should know to prevent foodborne illness from cracked eggs:

• Superficial cracks, or fresh cracks made at home: If an egg cracked recently and has been refrigerated, Coffman said you should use it immediately. "Bacteria can enter through the crack, even if it's refrigerated," she said.6 "You can also break the cracked egg into a clean container, cover it tightly, refrigerate, and use within two days."
• Store-bought eggs that are already cracked: According to Coffman, you should never purchase broken or cracked eggs, since it's not clear how long they've been exposed to potential contamination from Salmonella or other pathogens.
• Hard-boiled eggs that crack during cooking: If your eggs crack during boiling, Coffman said these eggs are generally safe—as long as the egg was clean and fresh to begin with, and is cooked to 160 degrees Fahrenheit.
• Soft-boiled eggs that crack during cooking: Most soft-boiled eggs have runny yolks, which often means they haven’t reached 160 degrees Fahrenheit and could be harboring bacteria, said Coffman. "If you choose to eat soft boil eggs, we recommend using pasteurized eggs to reduce the risk of foodborne illness," she said.

Other Ways to Tell If a Cracked Egg Is Still Safe to Eat

If you have a recently-cracked egg and want to be sure that it's safe for consumption, there are other metrics that can help you decide.

Smell

The best way to tell if an egg has gone bad is by its smell. "Spoiled eggs will have a bad odor," Woodman told Health.

Visual Cues

How an egg looks can help you determine whether it's safe, too. Eggs should generally hold their shape, the white should be clear, and the yolk should be a nice, yellow color, said Woodman. Eggs that are contaminated "may be cloudy, runny, or discolored," she added.

But not all changes in appearance are necessarily a sign that something is wrong. "Over time, you might notice that the egg white becomes thinner or the yolk sits a little flatter," added Maloberti. "These are typical signs of aging and don't mean the egg has gone bad."

Float Test

Every egg contains an air cell—a small pocket of air at the wide end of the egg, just beneath the shell, Maloberti explained. This is what creates the flattened spot on the end of a peeled hard-boiled egg.

Over time, as moisture and carbon dioxide escape through the shell's tiny pores, more air enters the egg and the air cell expands, she said.

So, some people use the "float test" to distinguish between good and bad eggs. The idea is that older, possibly contaminated eggs will float, while eggs that are safe to eat will sink. However, Maloberti said this test isn't always reliable.

"While the size of the air cell does increase with age, other factors like shell thickness or temperature can also cause an egg to float," said Maloberti. "Floating alone isn't a reliable method for checking freshness."

What to Do With Slightly Cracked Eggs

If you have an egg with a hairline break that was cracked at home or on the way home from the grocery store, handle it with caution, use it immediately, and heat it thoroughly, said Maloberti.

Eggs that have been cracked for longer periods of time or those with leaking cracks should be avoided. Throw them away in a regular trash, rather than a garbage disposal or compost, said Woodman. You can also put your discarded eggs in some kind of container to limit any odors or potential bacterial contamination, she said.

The Bottom Line

If you notice hairline cracks in eggs at the store, choose another carton, experts agreed.

But if you damage an egg at home, it may be safe to eat. Just cook it or use it in a baked dish right away to avoid the risk of bacteria seeping into the egg.

If you are unsure how the egg became cracked or if you notice it leaking, it's best to discard it.

"As the saying goes: 'When in doubt, throw it out.' With foodborne illness, it's always better to be safe than sorry," Coffman said.