How Long Mayonnaise Stays Fresh in Your Refrigerator

Unopened mayonnaise lasts three to four months past the printed date; opened jars last about two months

An unopened jar of mayonnaise will stay safe to eat for three to four months after the "best by" date printed on the lid, as long as it has been stored in a cool, dark place before you open it. Once you open the jar, the clock resets. An opened jar kept in your refrigerator at 40°F or below will last about two months from the day you first opened it, not from the printed date.

The reason mayonnaise lasts so long is its acidity and fat content. Mayonnaise is an emulsion—a mixture of oil, egg yolk, and an acid like lemon juice or vinegar. That acid creates an environment where most bacteria cannot grow. The high oil content also protects the egg from spoiling. This combination is why mayonnaise is one of the more stable condiments in your refrigerator, even after opening.

Key Takeaways

• Unopened mayonnaise keeps for three to four months past its printed date when stored in a cool pantry or refrigerator.
• Once opened, mayonnaise lasts about two months in the refrigerator at 40°F or below, regardless of the printed date.
• Store mayonnaise in the coldest part of your refrigerator, usually the back of a shelf or in the door if your door stays consistently cold.
• Discard mayonnaise if you see mold, smell an off odor, or notice the emulsion has separated into layers of oil and liquid.
• Homemade mayonnaise made with raw eggs lasts only three to four days and should be kept in the coldest part of your refrigerator.

Why the printed date is not the same as the expiration date

The date stamped on a jar of mayonnaise is a "best by" date, not a hard expiration. It tells you when the manufacturer believes the product will taste its best—when the flavor is sharpest and the texture is smoothest. After that date, mayonnaise does not suddenly become unsafe. It simply begins to lose quality: the flavor may flatten, the color may darken slightly, or the texture may become thinner.

Food safety and food quality are two different things. A jar of mayonnaise that is four months past its printed date and has been unopened in your pantry is still safe to eat. It may not taste as bright as it did on day one, but the acid and fat have done their job. The printed date is a quality promise, not a safety cliff.

How to store mayonnaise so it lasts the full two months after opening

Temperature is the single most important factor. Mayonnaise breaks down faster in warm conditions. Store your opened jar in the coldest part of your refrigerator—usually the back of a middle or lower shelf, where the temperature stays most consistent. If your refrigerator has a dedicated condiment shelf in the door, check whether that shelf stays at 40°F or below. Many door shelves are warmer than the main compartment because they are exposed to room temperature every time the door opens. A thermometer placed on a door shelf for a few hours will tell you whether it is cold enough.

Always close the lid tightly after each use. Mayonnaise exposed to air begins to oxidize, which can cause the color to darken and the flavor to turn slightly bitter. A loose lid also allows bacteria and mold spores from the air to land on the surface. Wipe the rim of the jar with a clean paper towel before closing the lid, especially if any mayonnaise has dried on the threads.

Do not double-dip. Use a clean spoon or knife every time you scoop mayonnaise from the jar. If you dip a spoon that has already touched food—especially protein or vegetables—you introduce bacteria into the jar. Those bacteria can multiply over time, even in the cold.

Signs that mayonnaise has gone bad

Mold is the clearest sign that mayonnaise is no longer safe to eat. Mold appears as fuzzy growth, usually white or green, on the surface or around the rim. If you see mold, throw out the entire jar. Do not try to scoop around it. Mold produces toxins that can spread through the mayonnaise even where you cannot see growth.

Smell the jar before using mayonnaise that is near the end of its two-month window. Fresh mayonnaise has a mild, slightly tangy smell. If it smells sour, rancid, or off in any way, discard it. Trust your nose—it is a reliable detector of spoilage.

Look at the texture and color. If the mayonnaise has separated into distinct layers of oil and a thin liquid, or if it looks curdled, the emulsion has broken down. This can happen if the jar was stored in a place that was too warm or if it was shaken vigorously. Separated mayonnaise is not necessarily unsafe, but it will not spread smoothly and the texture will be unpleasant. If you want to try to fix it, transfer it to a bowl and whisk it gently with a small amount of water or lemon juice, but if that does not work, it is better to start fresh.

Homemade mayonnaise has a much shorter window

If you make mayonnaise at home using raw eggs, it will last only three to four days in the refrigerator. Homemade mayonnaise lacks the preservatives and the industrial-scale acid balance of store-bought versions. The raw egg yolk is the limiting factor. Even though the acid in the recipe inhibits bacterial growth, it does not eliminate the small risk of salmonella from raw eggs.

Store homemade mayonnaise in the coldest part of your refrigerator, in a clean glass jar with a tight-fitting lid. If you are concerned about raw eggs, you can use pasteurized eggs, which are heat-treated to kill bacteria but are still technically raw. Pasteurized eggs are sold in most grocery stores near the regular eggs and will extend the safe storage time slightly, though three to four days is still the guideline.

What happens if mayonnaise sits out on the counter

Mayonnaise should not sit at room temperature for more than two hours. If your kitchen is warm—above 70°F—reduce that to one hour. Bacteria multiply rapidly in the "danger zone" between 40°F and 140°F. Even though mayonnaise is acidic, it is not acidic enough to stop all bacterial growth at room temperature.

If mayonnaise has been left out and you are unsure how long it has been sitting there, throw it out. The risk is not worth it. A fresh jar from the refrigerator costs far less than a foodborne illness. If you are taking mayonnaise to a picnic or outdoor event, keep it in an insulated cooler with ice packs, and return it to the refrigerator as soon as you get home.

Frequently Asked Questions

Can I freeze mayonnaise to make it last longer?

Freezing is not recommended. Mayonnaise is an emulsion, and freezing breaks down that structure. When it thaws, it will separate into oil and liquid and will not return to its original smooth texture. If you have a large jar you will not finish within two months, it is better to donate it or use it in recipes where texture matters less, like salad dressing or sandwich spread mixed with other ingredients.

Is mayonnaise safe to eat if it has been in the refrigerator for three months after opening?

At three months, mayonnaise is past the two-month window and should be discarded. The longer it sits, the greater the risk of mold or bacterial growth, even in the cold. If you have not used it by the two-month mark, it is time to replace it.

Why does mayonnaise sometimes turn brown or dark?

Oxidation causes mayonnaise to darken over time. This is a quality issue, not a safety issue. The egg yolk and oil react with oxygen in the jar, especially if the lid is not sealed tightly or if the jar has been opened many times. Dark mayonnaise is still safe to eat, but the flavor may be slightly bitter or flat.

Can I use mayonnaise past the printed date if it has never been opened?

Yes. An unopened jar will stay safe for three to four months past the printed date if stored in a cool place. Open it, smell it, and look at it. If it looks and smells normal, it is fine to use. The printed date is a quality marker, not a safety deadline for unopened jars.

What is the best way to tell if opened mayonnaise is still good?

Use the three-part test: look for mold or unusual color, smell for sourness or rancid odors, and check the texture for separation or curdling. If all three pass, and it has been less than two months since opening, it is safe to use. When in doubt, throw it out.