Should You Pasteurize Eggs at Home? A Serious Eats Investigation.

There are many excellent culinary uses for raw whole eggs, yolks, and whites, including homemade mayonnaise, Caesar dressing, meringue, and cocktails such as pisco sours and whiskey sours. But there are also some food safety concerns associated with consuming raw eggs, including potential exposure to Salmonella, which can cause stomach cramps, vomiting, diarrhea, fever, and—in rare cases—even death.

When you want to make a recipe that calls for raw eggs it's important to understand and mitigate the potential dangers, especially if you plan to serve the dish to anyone who is at greatest risk of becoming seriously ill from Salmonella (more on that below). At the very least, you may want to do as I do and shout, "This has raw eggs!" to anyone who's going to eat your potato salad that's dressed with a raw egg mayo. 

One option for avoiding raw eggs is to buy pasteurized ones. As with other foods like milk, pasteurizing eggs involves heating them to a temperature that destroys pathogens, but does not actually cook them. The main problem is that pasteurized eggs that are still in the shell can be very hard to find at US grocery stores. (It's easier to find pasteurized egg whites in cartons than it is to find whole pasteurized eggs, in our experience.) 

So what about pasteurizing eggs at home using the precisely controlled temperatures of a sous vide water bath? We found a couple of studies that suggest that this can be an effective method of killing Salmonella, which was more than enough to convince food nerds like us to break out our immersion circulators and try it out while delving into the minutia of pasteurization science.

To learn about the potential safety issues with home egg pasteurization, I spoke with James E. Rogers, Ph.D., the director of food safety research and testing for Consumer Reports. (Rogers holds a Ph.D. in microbiology and immunology and described himself as a "food safety curmudgeon" when I previously interviewed him for another article about egg safety for EatingWell—he must wonder why I keep trying to convince him to let me eat raw eggs.) Finally, I put eggs that I pasteurized using a sous vide immersion circulator to the test by making mayonnaise with the yolks and meringue with the whites—would they work as well as raw in these essential applications?

Here's what I learned about the potential benefits and dangers of home-pasteurization, plus instructions on how to home pasteurize if you want to give it a try once you understand the process and its limitations.  

The Potential Dangers of Eating Raw Eggs

The biggest food safety risk associated with raw eggs is Salmonella, especially Salmonella enterica, specifically Salmonella enterica serovar enteritidis (SE). Salmonella can be present on the shells of eggs as well as in the egg whites and yolks. Cooking kills Salmonella, and while fully cooked eggs are the safest, even sunny side up eggs are likely safe. But if there is Salmonella present in raw eggs, people who consume them are at risk of contracting the foodborne illness salmonellosis, which, as mentioned above, can cause gastrointestinal distress, hospitalization, and even death. 

At the time of this article's original publication (July, 2024), the CDC had no reports of active Salmonella outbreak investigations related to commercially distributed eggs in the US, but unfortunately on September 6, 2024, the CDC reported a Salmonella outbreak linked to eggs with a report of 65 illnesses and 24 hospitalizations at the time of reporting. (Eggs are not the only food that can cause foodborne illnesses—in fact, in June of 2024, the CDC issued a warning about a Salmonella outbreak linked to cucumbers. They reported 551 illnesses and 155 hospitalizations before the outbreak was declared over.)

While Salmonella enterica is the most common foodborne pathogen associated with eggs, there are other pathogens that have been linked to eggs, including Listeria, a pathogen that can cause illness and serious pregnancy complications, including miscarriage and stillbirth.

The highest risk groups for contracting and becoming seriously ill from salmonellosis include those with weakened immune systems, adults age 65 and older, children under five, and pregnant people, according to the CDC and other sources. But if you're a healthy 68 year old with a passion for Caesar salads, are we going to tell you to never eat unpasteurized raw eggs? No, we are not, because we understand that people take calculated risks all the time and the occasional consumption of a raw egg is not at the top of the list of most dangerous things people regularly do. (The fact is leafy greens are linked to far more recalls and foodborne illnesses than eggs, so if it's a numbers game you're playing, you might as well skip that Caesar altogether.)

For legal reasons, though, we need to be very clear that experts and food safety authorities like Rogers and the CDC decidedly disagree with our more flexible attitude, and so the official guidance is to avoid raw eggs, especially among those in the defined high-risk groups. If you have any concerns at all, you should follow that official guidance.

For the rest of us, it's really a cost-benefit analysis. Like me and most of the Serious Eats staff, you might decide that the risks are worth the reward. Or, you might be like Rogers, and take a more "conservative" approach and choose to avoid raw eggs unless they've been commercially pasteurized.

Understanding the Science of Pasteurization: Assessing Risk by the Numbers

The thing about doing a food safety cost-benefit analysis is you need to understand the underlying data and logic before you can make any informed decisions of your own. So before we dive into at-home egg pasteurization and its potential benefits and limitations, we first need to learn how food-borne illness risks are assessed and mitigated by health and food authorities.

In the case of eggs, the goal is not necessarily to reduce the number of bacteria in a given egg to zero—which is often impossible without rendering the food inedible—but to reduce it to a level at which the risk of causing illness is tolerably low from a public-health standpoint. Because bacteria can number in the tens or hundreds of thousands (if not more) in a contaminated serving of food, the goal of pasteurization is to drive the number of bacteria down exponentially until safe levels are reached.

This exponential decrease in bacteria is expressed mathematically as a log reduction, in which each reduction represents a tenfold decrease in the number of surviving bacteria: In a 1-log reduction, one in ten bacteria will survive; in a 2-log reduction, one in 100 bacteria will survive; and in a 3-log reduction, one in 1,000 bacteria will survive. It continues in powers of ten from there.

According to USDA guidelines, a 5-log reduction is the standard for pasteurized eggs. This translates to a 100,000-fold decrease in bacterial colony forming units (CFUs), which can also be expressed as a 99.999% reduction. Wow, I can hear some of you thinking, a 99.999% reduction in nasty bacteria sounds pretty dang good to me! And based on the fact that a lot of very smart scientists came up with that guideline, you're probably right. But percentages can be deceptive, so let's look more closely at the raw numbers—it will help us to understand home pasteurization risks later.

First, it helps to know that even a single viable salmonella cell can cause infection. Just one! Sure, the risk is low—this study states that consuming a single viable cell of salmonella comes with a .25% probability of illness—but the risk is there. How common is it to encounter eggs contaminated with salmonella in the US? According to CDC estimates, only 1 in every 20,000 eggs in the US is. As you can see, the odds are in any one individual's favor, but multiplied across a large population of eager egg eaters (say that three times fast), and the risks of illness become more considerable. The CDC estimates that salmonella causes "about 1.35 million infections, 26,500 hospitalizations, and 420 deaths in the United States every year."

Next, let's factor in how much unwanted bacteria one is likely to find in a single contaminated egg. According to this study, the average number of CFUs varies heavily depending on many factors but is somewhere between 10,000 and 100,000 on the shell alone (not including the interior whites and yolk, which can also be infected, though to a lesser extent). Based on this, even at the higher end of the average range, the USDA guideline of a 5-log reduction would tend to get us down to a sole surviving viable bacterium.

What does that 5-log reduction via egg pasteurization translate to in terms of real-world infections? According to a 2005 USDA and FDA risk assessment, a 5-log reduction is enough to lower the total number of infections annually in the US from 130K to 19K. As you can see, it's not enough to get the risk of infection down to zero, but it's a considerable reduction with a clear public health benefit.

At this point, it's critical to point out that egg pasteurization doesn't happen in a vacuum. There are scores of variables that can complicate the picture. Things like storage temperatures before and after pasteurization will have a huge effect on these numbers—improper storage can pretty much undo any benefit created by pasteurization, which should be taken into account for all stages of egg handling, but also for storage of foods made with raw or pasteurized eggs. Meaning, just because you're using pasteurized eggs in an uncooked dish doesn't mean you can get sloppy with food handling and storage. One careless step like letting the food sit out at room temperature for too long and what had been a low-risk meal could grow into a mouthful of misery.

At-Home Sous Vide Egg Pasteurization 101

I know you've had to read a lot to get to this point, but it's all going to be very useful in making a decision about whether you're comfortable attempting to pasteurize eggs at home or not.

If you search around, you are likely to find several different methods of at-home pasteurization, but the most reliable research and methods we found are focused specifically on sous vide pasteurization, which makes sense—pasteurization is largely about highly precise temperature control over extended periods of time, and that is exactly what the immersion circulators used for sous vide cooking do well. When submerged in a pot or other vessel of water, they can maintain a set temperature for extended periods of time while continuously circulating the heated water to minimize variations in temperature. This ability to hold a precise temperature over time makes them the most compelling tool for home pasteurization.

As Kenji notes in his guide to sous vide chicken, the reduction in bacterial loads in food is a function of both temperature and time. With eggs, the key is to hold the eggs at the correct temperature for long enough for the heat to penetrate all the way to the center of the egg, since Salmonella and other pathogens can be present throughout the egg—not just on the shell, as is a common misconception.

What is the correct temperature for pasteurized eggs? Generally speaking, it's one that is hot enough that, given enough time, it can significantly lower the risk of pathogens but still cool enough that the egg retains its ability to function like a raw one in a recipe. We found more specific time and temperature guidelines in a couple different research papers. In "Immersion Heat Treatments for Inactivation of Salmonella Enteritidis With Intact Eggs," published in 1997 in the Journal of Applied Microbiology, they tested pasteurizing eggs for 50 to 57.5 minutes at a water temperature of 58°C (136.4°F) and within 65-75 min at 57°C (134.6°F), and found that at this range, "Six pooled strains of Salm. enteritidis (ca 3 x 10(8) cfu, inoculated near the centre of the yolk) were completely inactivated," leading the study authors to conclude, "Immersion-heated shell eggs could provide Salmonella-free ingredients for the preparation of a variety of minimally-cooked foods of interest to consumers and foodservice operators."

A second study, "Inactivation of Salmonella in Shell Eggs by Hot Water Immersion and Its Effect on Quality," published in 2016 in the Journal of Food Science, tested eggs at various times and temperatures and also looked at the quality of the eggs pasteurized through hot water immersion. They found that the strains of Salmonella they tested were reduced by 4.5 log at both hot water immersion treatments of 56.7°C (134.06°F) for 60 minutes and 55.6°C (132.08°F) for 100 minutes. A 4.5-log reduction translates to a 99.997% reduction in pathogens, or roughly three surviving viable bacteria per 100,000.

They also looked at the quality of eggs treated with heat immersion and found that while the yolks were largely unaffected, the whites were altered enough that they performed differently in whipping tests, taking much longer to whip. "In summary, the hot water immersion process inactivated heat resistant SE in shell eggs by 4.5 log, but also significantly affected several egg quality characteristics," the authors report.

Is Pasteurizing Eggs at Home Safe?

So, phrases like "completely inactivated" and 99.997% reduction sound great, right? Well, not so fast, says Rogers. He has a number of concerns with home-pasteurization. For starters, while commercially pasteurized eggs have been subjected to rigorous standards to be sure the time, temperature, and method is the exact same every time, and a portion of the eggs are also tested after pasteurization to be sure the pathogens are dead, there are numerous points in the home-pasteurization process when things can go off the rails.

"You're expecting consumers to get that right every time—that their temperature is right, that their thermometer is accurate, that the sous vide machine readout is accurate," Rogers says. "The problem is that we know from studies that you could ask consumers, 'How many times did you wash your hands?' They'll say five and then if you look up the video it might have been one, right?" He says if you cut corners, cut down on time, or if your thermometer or immersion circulator is off by a couple of degrees, any Salmonella that's present could be passed along to the final dish and make you or your guests sick.

Rogers says it's also important to take into account variables like how many eggs you're pasteurizing and the fact that the heat needs to penetrate all the way to the center of the yolk for the proper amount of time in order for the eggs to be properly pasteurized. " I think that there are so many variables that a consumer would have to get right in order to lower their risk," he says. That said, he concedes that while he would never be convinced that the method is guaranteed to work, he does allow that home pasteurization—if done exactly right every time—could lower the risk.

While I may have made marginal headway in my game of "Convince Jim Rogers to Let Me Eat Raw Eggs," I have to accept that I am never going to get a food safety stickler to fully endorse home pasteurization. But based on my research—and despite the shortcomings—I think I can safely say that using a sous vide setup to pasteurize eggs can reduce the risks of eating raw eggs far more than simply throwing up your hands and saying, "Aw, screw it, I'm just gonna eat raw-egg mayo because I have no hope of ever meeting the official guidelines."

All in all, we can pretty safely conclude the following:

• Home pasteurization using sous vide is inherently prone to human and machine error, and therefore is not nearly as reliable or safe as commercial pasteurization.
• The hot water method's estimated 4.5-log reduction as described in the 2016 Journal of Food Science study would significantly lower infection risk, assuming the process is done correctly and the gear is properly calibrated and in working order. To emphasize Rogers' point, that's a pretty big "if," but even if we do avoid human and mechanical error, it's still not as effective as commercially pasteurized eggs' 5-log reduction.

Does this mean I would serve home-pasteurized raw eggs to an elderly, immunocompromised, or pregnant friend, relative, or stranger? No. I do not want to kill grandma. But I myself feel totally comfortable eating the mayo and meringue made with the eggs pasteurized with sous vide following the recommended times and temperatures.

Home pasteurization is arguably a lot better than doing nothing, so if you're a raw egg lover who also owns an immersion circulator, it seems to me it's worth taking this extra step to reduce risk. 

Tested: How Well Do Sous-Vide Pasteurized Eggs Work in Mayos and Meringues

All of the above is the theory. Now we need to consider the practical side: How do sous-vide pasteurized eggs work in the types of recipes that require raw eggs?

To find out, we took out a trusty immersion circulator and tested a batch of 11 large eggs at a temperature of 135°F (57.2°C) for 90 minutes, starting from the time the water bath reached 135°F (57.2°C). We arrived at this temperature and timeframe by slightly padding both the ideal temperature and time of 65 to 75 minutes at 57°C (134.6°F) outlined in the paper "Immersion Heat Treatments for Inactivation of Salmonella Enteritidis With Intact Eggs." The eggs were fully submerged in a large pot with enough space for the water to circulate freely around them. After the 90 minutes at 135°F, we immediately transferred the eggs to an ice bath to quickly cool them to a safe holding temperature. 

Results: Home-Pasteurized Eggs Compared to Unpasteurized Eggs in Recipes

Appearance and texture: After chilling the eggs, I separated the yolks from the whites and examined them. The yolks looked completely unchanged by the process, but the whites were noticeably cloudy and felt a bit more viscous than I'd expect for a truly raw egg, signs that some of the proteins in the egg white had started to coagulate. "It's not solid or semi-solid like a soft boiled egg, but there are still some changes probably going on with that white," says Rogers of the lengthy exposure to moderate heat.

After the visual examination, I put the eggs to the test in two popular recipes that are dependent on a raw egg's ability to emulsify fats (mayo) and trap air (whipped egg whites)—two things that cooked eggs are not nearly as capable of doing, if at all. 

Mayonnaise test: For my first test, I used one home-pasteurized egg yolk, 1 tablespoon freshly squeezed lemon juice, 1 cup of extra-virgin olive oil, and kosher salt to whisk together a basic mayonnaise. The mayo came together exactly as I would expect it to with an unpasteurized egg—the egg emulsified the mixture beautifully and fairly quickly. The flavor and texture were also excellent, so I consider this test a total success. The only way it would have been more successful is if we had some cold poached lobster or crab to dip into the mayonnaise. 

Meringue test: For this test, I enlisted the help of pastry pro Genieve Yam to make meringue with the egg whites following the French meringue in her meringue cookie recipe, although instead of baking the meringue into cookies, we left it unbaked as you would if you wanted to use the meringue to top a pie.

The egg whites took more than double the time of  unpasteurized eggs to get frothy and then to be whipped into an airy meringue. Rogers says this is likely to be due to the denaturing of the proteins—the same thing that made the egg whites cloudy. But after the extra-long whipping time in the stand mixer, the egg white–sugar mixture did eventually transform into a meringue that I'd describe as a success. The volume was slightly less than I would have expected from a truly raw egg, but the final texture and flavor of the meringue were excellent. 

How to Pasteurize Eggs at Home Using Sous Vide

If you decide to pasteurize eggs at home using sous vide after reading about the possible risks, here's how to do it. Note that while Salmonella grows very slowly at refrigerator temperatures, I still recommend using eggs you've home-pasteurized immediately rather than storing them. And keep in mind that if there is any Salmonella present in the eggs, it can repopulate over time, so eating food made with the eggs sooner rather than later is the best bet. It's especially important not to let it sit out for more than two hours (one hour at higher temperatures). 

1. Start with fresh eggs with no visible shell damage, such as cracks. 
2. Submerge up to a dozen eggs in a large pot of water fitted with an immersion circulator. Be sure there is space around the eggs for the water to circulate freely.
3. Set the immersion circulator to 135°F (57.2°C). Once the temperature has reached 135°F (57.2°C), start a timer for 90 minutes.
4. Using a high-quality instant-read or probe thermometer, continuously monitor the temperature of the water bath to confirm the immersion circulator is maintaining the set temperature. 
5. After 90 minutes, immediately transfer the eggs to an ice bath. Use the whole eggs, whites, or yolks as you would regular raw eggs. 

The Verdict

Though it's not guaranteed to work, we believe that home pasteurization using sous vide is a good method of improving the safety of raw eggs. The eggs we tested with this method worked well in recipes, though egg whites took longer to whip. Overall, if you are concerned about the risks of raw eggs and can get your hands on commercially pasteurized raw eggs, that would be the best choice in recipes that call for raw egg, but we like the sous vide method as an alternate way to reduce—but not eliminate—the dangers of eating raw eggs.