Are Runny Egg Yolks Safe to Eat?

New York Times

19-02-2025

Sunny side-up, over easy, lightly scrambled, soft-boiled, poached: Americans love eating eggs when they're still runny, despite the general understanding that raw or undercooked eggs aren't good for you.
When you cook an egg, the heat that solidifies its whites and yolks kills pathogens like salmonella and bird flu. That's why food safety officials recommend cooking eggs until both parts are firm.
But how unsafe are runny yolks really?
That depends on how much risk you're willing to accept, said Felicia Wu, a professor of food safety, toxicology and risk assessment at Michigan State University.
'If you look at the eggs typically purchased in the United States, most of them are perfectly safe to eat in a runny state,' she said. 'It's just that we don't know when there's an individual egg that contains some risk.'
Salmonella is a real concern.
Eggs can carry harmful bacteria, including E. coli and campylobacter. But salmonella — the leading cause of food poisoning-related deaths nationwide — is by far the biggest hazard, said Dr. John Leong, a professor of molecular biology and microbiology at Tufts University.
Recent data on salmonella-infected eggs is hard to find. One widely cited study from 2000 suggested that one in every 20,000 eggs carries the bacteria. This might not sound like a lot, but given how many eggs Americans eat — about 250 per person on average in 2023 — that risk can add up.
Salmonella can cause fevers, stomach cramping, diarrhea, vomiting and in rare cases, lingering joint pain.
And while most recover on their own or with antibiotics, around 26,500 people with salmonella are hospitalized and about 420 die of their infections each year. Salmonella is especially dangerous for older people, young children and those who are pregnant or immunocompromised. Public health officials are growing more concerned about antibiotic-resistant salmonella strains, Dr. Leong said.
It's hard to determine the exact likelihood that a given egg would carry salmonella, because not every egg that ends up on your plate gets tested for the bacteria, said Julie Garden-Robinson, a professor and food and nutrition expert at North Dakota State University.
Hens lay eggs and pass feces through a single opening, which can leave bacteria on eggshells. The federal government requires most sellers with 3,000 or more laying hens to sanitize the outside of eggs before they're sold. This lowers — but doesn't completely eliminate — the risk of salmonella ending up on an eggshell. Smaller farms and those that sell their eggs directly to consumers don't have to follow the federal washing rules, although they might follow state and local requirements.
But even sanitized eggs may carry salmonella since the bacteria can also get into the egg yolk and white, Dr. Garden-Robinson said. There isn't data to show whether most egg-related salmonella infections come from bacteria inside the egg or on its surface, Dr. Wu said.
Bird flu is less of a concern.
Although the recent bird flu outbreak is killing millions of hens and sending egg prices surging, experts say the evidence currently suggests that the virus is unlikely to end up in an egg you're eating.
That's mainly because infected hens die of bird flu before they can lay eggs, said Dr. John Swartzberg, an emeritus professor of infectious diseases and vaccinology at the University of California, Berkeley.
If the virus did make its way to your egg carton, though, cooking the egg until the whites and yolks are both firm would kill it.
There are ways to lower your risk.
If you love runny yolks too much to give them up for good, it might be OK to enjoy them occasionally, depending on your health and your own risk tolerance.
'You obviously will not get sick every time you eat an undercooked egg,' Dr. Garden-Robinson said.
And you don't have to cook yolks until they're so hard they crumble to reduce your salmonella risk. Jammy or slightly set yolks with a custard-like texture are less risky than runny yolks, said Dr. Indu Upadhyaya, a food safety expert at the University of Connecticut.
To further protect yourself, experts shared several other recommendations: