Cooking eggs to an internal temperature of 160°F (71°C) kills Salmonella reliably. That means firm yolks and firm whites, not runny centers. For recipes that call for lightly cooked or raw eggs, you have other options: home pasteurization in a water bath, using store-bought pasteurized eggs, or acidification with vinegar or lemon juice.
How Common Is Salmonella in Eggs?
In the United States, roughly 1 in 20,000 eggs (0.005%) carries Salmonella. That’s a low number, but with billions of eggs consumed each year, it adds up. The bacterium can live inside the egg before the shell even forms, meaning a clean, uncracked shell doesn’t guarantee safety. Contamination rates are considerably higher in other countries, reaching up to 5.6% in parts of China.
Salmonella multiplies rapidly between 40°F and 140°F, the so-called “danger zone.” A contaminated egg sitting on a warm counter gives bacteria the chance to grow from a harmless trace into a dose large enough to cause illness. Refrigerating eggs at 40°F or below keeps bacterial counts from climbing, but it doesn’t kill what’s already there. Only heat or sustained acidity can do that.
The Simplest Method: Cook Eggs Thoroughly
The USDA recommends cooking eggs until both the white and yolk are completely firm. For egg dishes like quiches, casseroles, and frittatas, the center should reach 160°F on a food thermometer. Leftovers containing eggs should be reheated to 165°F before eating.
A firm yolk isn’t just a visual cue. Salmonella actually dies faster in yolk than in egg white because the fat content conducts heat more efficiently. Research shows that at 140°F (60°C), Salmonella in yolk is reduced to safe levels in under a minute, while egg white requires several minutes at that same temperature to achieve comparable results. This is why a soft-boiled egg with a runny yolk carries more risk than most people assume: the white may look set, but the cooler center of the yolk may not have reached a lethal temperature.
For scrambled eggs, omelets, and fried eggs, cooking until no visible liquid egg remains is the practical rule. If you’re using a thermometer, 160°F at the thickest point is your target.
Pasteurizing Eggs at Home
If you need eggs for recipes where they won’t be fully cooked (Caesar dressing, hollandaise, homemade mayonnaise, cookie dough), you can pasteurize whole shell eggs yourself using a sous vide circulator or a carefully monitored pot of water.
Pasteurization doesn’t cook the egg. It holds it at a temperature high enough to kill bacteria but low enough to keep the proteins from setting. The key variable is time: lower temperatures need longer immersion. Research from the BC Centre for Disease Control found that holding eggs at 136°F (58°C) for 50 to 57 minutes achieves a full 7-log reduction of Salmonella, meaning it eliminates 99.99999% of the bacteria. At 135°F (57°C), you need 65 to 75 minutes. Below about 131°F (54.4°C), even two hours of immersion only achieved a partial reduction, making those temperatures inadequate.
For practical home use, a water bath set to at least 135°F (57°C) for 75 minutes provides a solid safety margin. A sous vide circulator is ideal because it holds temperature precisely. If you’re using a pot on the stove, you’ll need to monitor with a thermometer constantly, since even a few degrees of fluctuation changes the outcome significantly. After pasteurization, the eggs can be used immediately or refrigerated for later use. The whites may look slightly milky but will whip and cook normally.
Store-Bought Pasteurized Eggs
Commercial pasteurized eggs, sold in the shell or as liquid products, are the easiest option for raw or lightly cooked applications. The USDA requires liquid egg products to be pasteurized before sale and considers a 5-log reduction of Salmonella (99.999% eliminated) the safety standard for products eaten without further cooking.
The commercial process for whole liquid egg holds it at 140°F (60°C) for 3.5 minutes. Yolk is pasteurized at slightly higher temperatures, 142°F for 3.5 minutes, because its higher fat and protein content insulates bacteria. In-shell pasteurized eggs (sold under brands like Davidson’s) go through a similar carefully timed heat treatment. These eggs are your safest choice for recipes like eggnog, tiramisu, or aioli.
Using Acid to Kill Salmonella
Vinegar and lemon juice can reduce Salmonella in raw egg yolk, but the details matter more than most recipes acknowledge. Vinegar is significantly more effective than lemon juice at the same pH level.
Research published in the Journal of Food Protection found that acidifying egg yolk with vinegar (5% acetic acid or stronger) to a pH of 3.9 and holding it at room temperature for two hours reduced Salmonella by more than 99.99%. A ratio of roughly 0.82 parts vinegar to 1 part egg yolk achieves this pH. If refrigerated instead, the same reduction took about 24 hours.
Lemon juice tells a different story. At the same pH of 3.9, lemon juice actually allowed Salmonella to grow at room temperature. You’d need to push the pH down to 2.9, which requires about 1.23 parts lemon juice to 1 part yolk, and wait 24 hours to get the same level of safety. That’s far more lemon juice than most recipes call for, and it changes the flavor considerably.
The takeaway for homemade mayonnaise or dressings: vinegar-based recipes are genuinely safer than lemon-based ones, especially if you let the mixture sit at room temperature for at least two hours before refrigerating. But acid alone is not a quick fix. If you mix it and serve it immediately, you haven’t given the acid enough contact time to meaningfully reduce bacteria.
Why Washing Eggs Doesn’t Help
Washing eggs at home doesn’t remove Salmonella and can actually make things worse. The eggshell has a natural protective coating called the cuticle that seals the tiny pores in the shell. Research found that washing damages this cuticle significantly, and washed eggs were penetrated by Salmonella at roughly double the rate of unwashed eggs. In one experiment using sensitive detection methods, 74% of washed eggs showed bacterial penetration compared to 36% of unwashed eggs.
In the US, commercial eggs are already washed and sanitized at the processing plant under controlled conditions, which is why they must be refrigerated afterward. Washing them again at home strips away whatever remaining protection exists without adding any meaningful safety benefit. If you’re buying farm-fresh unwashed eggs, refrigerate them as-is and rely on cooking temperature, not washing, to handle any contamination.
Quick Reference by Use Case
- Fried, scrambled, or boiled eggs: Cook until whites and yolks are completely firm. No thermometer needed if nothing is runny.
- Casseroles, quiches, custards: 160°F at the center, verified with a food thermometer.
- Homemade mayo or dressings: Use pasteurized eggs, or acidify yolk with vinegar (0.82:1 ratio) and hold two hours at room temperature before serving.
- Raw applications (eggnog, mousse, tiramisu): Use store-bought pasteurized eggs or pasteurize at home in a 135°F water bath for 75 minutes.
- Reheated leftovers with egg: Bring to 165°F throughout.