Mayonnaise is one of those everyday kitchen staples that can sit in the refrigerator for weeks before anyone remembers when it was opened. Whether you use it for sandwiches, burgers, potato salad, or creamy homemade dressings, knowing how long mayonnaise stays fresh can help you reduce food waste and make safer choices in the kitchen.

The good news is that commercially prepared mayonnaise can often last for a considerable time after opening when it is handled and stored correctly. However, its shelf life depends on the product, refrigeration temperature, and how carefully it is used.

So, how long can you keep an opened jar of mayonnaise, and when should you throw it away? Here is what every home cook should know.

How Long Does Opened Mayonnaise Last?

As a general guideline, commercially prepared mayonnaise typically keeps for about two months in the refrigerator after opening, provided it has been continuously refrigerated and handled properly. Always check the manufacturer’s storage instructions, since products and recommendations can vary.

For the best quality and safety, keep your refrigerator at 40°F (4°C) or below. Return mayonnaise to the refrigerator promptly after use rather than leaving it on the counter while preparing a meal.

Remember that the printed date on the container and the date you opened it are not necessarily the same thing. Writing the opening date on the lid can help you keep track of how long the jar has been in use.

Why Store-Bought Mayonnaise Lasts Longer Than Homemade

Commercial mayonnaise is generally made with pasteurized eggs and carefully controlled levels of acidity. Ingredients such as vinegar or lemon juice help create an environment that limits the growth of many harmful bacteria.

However, this does not mean mayonnaise is immune to contamination. Every time you open the jar, use a utensil, or handle the lid, there is a possibility of introducing crumbs, moisture, or microorganisms.

Homemade mayonnaise requires extra caution, particularly when it contains raw eggs. For a safer option, use pasteurized eggs and follow a reliable recipe with clear refrigeration instructions. Homemade mayonnaise should not automatically be given the same storage period as a commercial product.

Signs Your Mayonnaise May Have Gone Bad

Before using a jar that has been sitting in your refrigerator, check for noticeable changes.

• Unusual odor: A sour, rancid, or otherwise unpleasant smell can indicate spoilage.

• Visible mold: Discard the entire jar if you notice mold on the surface, around the lid, or along the rim.

• Unexpected discoloration: Significant changes in color may indicate that the product is no longer in good condition.

• Unusual texture: Changes that cannot be explained by normal separation may be a reason to discard the mayonnaise.

Keep in mind that appearance and smell cannot reliably confirm that a food is safe. If the mayonnaise has been stored improperly, has exceeded the recommended storage period, or leaves you uncertain about its handling history, it is safer to throw it away. Never taste questionable mayonnaise to determine whether it is still good.

Simple Habits That Help Mayonnaise Stay Fresh

A few small changes can help maintain the quality of your mayonnaise and reduce the risk of contamination.

Always use a clean spoon or knife when taking mayonnaise from a jar. Avoid dipping a utensil into the container after it has touched meat, bread, or other foods.

Close the lid tightly after each use and return the jar to the refrigerator promptly. Keep it on an interior shelf where temperatures tend to remain more consistent, rather than relying on a refrigerator door shelf that experiences frequent temperature changes.

Mayonnaise should also not be left at room temperature for extended periods. As a general food-safety rule, perishable foods should not remain unrefrigerated for more than two hours, or one hour when temperatures exceed 90°F (32°C).

What About Mayonnaise-Based Salads?

Potato salad, tuna salad, chicken salad, and egg salad require special attention because their ingredients can support bacterial growth if they are not kept cold.

Even when prepared with fresh commercial mayonnaise, these dishes should generally be refrigerated promptly and consumed within three to five days. The mayonnaise itself is not necessarily the main source of risk; other ingredients and improper temperature control can contribute to foodborne illness.

For picnics, barbecues, and outdoor gatherings, keep mayonnaise-based salads chilled in a cooler with sufficient ice or cold packs.

Should You Freeze Mayonnaise?

Freezing commercial mayonnaise is generally not recommended because it can cause the mixture to separate and develop an unpleasant texture after thawing. Rather than freezing an opened jar, purchase a container size that matches your household’s needs and use it within the recommended refrigerated storage period.

The Bottom Line

Opened commercial mayonnaise can generally be kept in the refrigerator for about two months when stored properly, according to USDA food-storage guidance. However, the manufacturer’s instructions should always take priority, and homemade mayonnaise requires different precautions.

By refrigerating mayonnaise promptly, using clean utensils, and paying attention to storage dates, you can enjoy this versatile condiment while reducing unnecessary food waste. When its storage history is uncertain or you suspect spoilage, choosing a fresh jar is the safer option.