For most healthy adults, eating runny eggs carries a small but real risk of Salmonella infection. The FDA recommends cooking eggs until both the yolk and white are firm, which means reaching an internal temperature of 160°F (71°C). That said, millions of people eat runny eggs regularly without getting sick, and the actual risk depends on several factors: where your eggs come from, how they’ve been stored, and your own health status.
Why Runny Eggs Carry Risk
The concern with undercooked eggs comes down to one bacterium: Salmonella. It can get inside an egg in two ways. The first is through the shell after the egg is laid, as bacteria from the environment gradually work their way inward. The second happens before the egg even exists as an egg: if the hen’s reproductive organs are infected, the bacteria get deposited directly into the forming egg. Either way, Salmonella can migrate into the nutrient-rich yolk and multiply there.
Cooking an egg until the yolk is firm kills the bacteria reliably. A runny yolk, by definition, hasn’t reached the temperature needed to do that. Not every egg contains Salmonella (the vast majority don’t), so eating a runny egg is more like a small gamble than a guaranteed illness. But you can’t tell from looking at an egg whether it’s contaminated.
What Happens if You Do Get Sick
Salmonella symptoms typically appear anywhere from 6 hours to 6 days after eating a contaminated egg. The most common signs are diarrhea, stomach cramps, fever, nausea, and vomiting. Some people also experience chills, headaches, or blood in the stool. The illness generally lasts a few days to a week, though diarrhea can persist for up to 10 days, and it can take several months for your digestion to fully return to normal.
Most people recover without medical treatment. In severe cases, though, the infection can spread from the intestines into the bloodstream and then to other parts of the body, which can become life-threatening without antibiotic treatment.
Who Should Avoid Runny Eggs Entirely
The risk of serious complications is significantly higher for certain groups: young children, adults over 65, pregnant women, and anyone with a weakened immune system. That includes people with HIV/AIDS, cancer, diabetes, or those who’ve had an organ transplant. For these groups, the FDA’s guidance is straightforward: cook eggs until the yolk is firm, and don’t eat foods containing raw or undercooked eggs.
If you’re a healthy adult with a normal immune system, the odds of getting severely ill from a single runny egg are low. But they’re not zero, and they increase with frequency. Someone who eats sunny-side-up eggs every morning is rolling the dice more often than someone who does it occasionally.
How Storage Affects Your Risk
How your eggs are handled before they reach your plate matters more than most people realize. Salmonella multiplies fastest at warm temperatures. Research has shown that eggs stored at room temperature (around 77°F or 25°C) shortly after being laid have the highest rates of internal contamination. Refrigerating eggs at 40°F (4°C) significantly slows bacterial growth and reduces the chance that any Salmonella present on the shell will penetrate inward.
This is why keeping eggs refrigerated from the store to your kitchen is important, especially if you plan to cook them with a runny yolk. Leaving eggs out on the counter for hours before cooking increases the bacterial load inside, which means even brief cooking may not be enough to make them safe.
The UK Approach Is Different
If you’ve traveled to the UK, you may have noticed that runny eggs are served freely, even to pregnant women. That’s because the UK uses a different prevention strategy. Eggs carrying the British Lion mark come from hens that have been vaccinated against Salmonella, and the program has been so successful that UK food safety authorities now consider these eggs safe to eat runny, even for vulnerable groups like babies and pregnant women.
The US does not have an equivalent nationwide vaccination program, which is why American food safety guidelines remain more cautious. If you’re in the US, standard grocery store eggs are not produced under the same system, and the FDA’s recommendation to cook yolks firm still applies.
Pasteurized Eggs: The Safer Runny Option
If you love runny yolks but want to minimize risk, pasteurized shell eggs are your best option. These eggs have been heat-treated at temperatures high enough to kill Salmonella but low enough to keep the egg raw inside. They look and taste like regular eggs but are significantly safer to eat undercooked. You can find them in most major grocery stores, often labeled clearly as “pasteurized.”
It’s also possible to pasteurize eggs at home using a sous vide setup or a precise water bath, though the process requires careful attention to time and temperature. Research shows that holding shell eggs at 136°F (58°C) for 50 to 57 minutes achieves a full elimination of Salmonella. Lower temperatures require longer times: at 132°F (55.6°C), you’d need about 100 minutes total. The minimum practical guideline is at least 45 minutes at no lower than 144°F (62°C). Getting this wrong means you’ve warmed the egg without actually killing the bacteria, so if you go this route, use a reliable thermometer and timer.
Practical Ways to Reduce Risk
- Buy refrigerated eggs and keep them cold. Don’t leave them sitting on the counter before cooking.
- Use eggs before their expiration date. Older eggs have had more time for any bacteria present to multiply.
- Choose pasteurized eggs for dishes that involve runny yolks, homemade mayo, or any recipe where the egg won’t be fully cooked.
- Cook eggs to 160°F (71°C) if you want to eliminate risk entirely. At that temperature, both the yolk and white will be firm.
- Wash your hands after handling raw eggs, and don’t let raw egg contact other foods or surfaces you’ll eat from.
For a healthy adult eating fresh, properly refrigerated eggs, the occasional runny yolk is a low-probability risk that most people accept without a second thought. But it is a risk, and understanding what drives it lets you make a more informed choice about how you like your eggs cooked.