Does Mayonnaise Go Bad? (2024)

Mayonnaise is a common ingredient in many households which means you have probably once asked: “Does mayonnaise go bad?” while cleaning out the fridge or pantry. Since eggs are one of the main ingredients in mayonnaise, the shelf life differs quite a bit from other condiments, such as mustard or ketchup, which typically last longer.

Understanding the shelf life of mayonnaise is important to keep yourself healthy and reduce the risk of foodborne illness. Whether you're spreading it on a sandwich, mixing it into potato salad or incorporating it into any other recipe, knowing if the mayo is safe to use is essential. So, if you're wondering if that jar in your kitchen is still safe to eat, here's what you need to know about mayonnaise's shelf life and signs it has gone off.

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• Does Mayonnaise Expire?
• How Long Does Mayonnaise Last After the Expiration Date?
• How To Tell if Mayonnaise Is Bad
• Can You Eat Expired Mayonnaise?

Does Mayonnaise Expire?

So, does mayonnaise go bad? In short, yes, it does. Both commercially made and homemade mayonnaise will eventually spoil with time. Storing mayo in the fridge is the best way to keep it in good condition. However, commercial and homemade mayonnaise differ in how long they will last before going bad.

Commercially-made mayo, such as the type you would purchase from the store, typically has preservatives added to the recipe. These preservatives are meant to extend the shelf life. With these types of mayonnaise, the eggs are usually pasteurized, which also lowers the levels of harmful bacteria. For these reasons, commercially made mayonnaise will have a longer best-by date than the homemade variety.

In contrast, homemade mayonnaise has a much shorter viability. Being made in your own home, you’re probably not adding the preservatives that extend the condiment’s life. Homemade mayo is also usually made with raw eggs and these aren’t typically pasteurized. This increases the risk of harmful bacteria and lowers the amount of time it’s safe to eat the product. It’s generally suggested to eat homemade mayonnaise within four days of making it.

Does Mayonnaise Go Bad in the Fridge?

Now knowing that mayo goes bad, you may also want to answer: “Does mayonnaise go bad in the fridge?” Yes, it can. Commercially made mayo is shelf-stable as long as it's unopened and the seal isn’t broken. Once you open the jar, mayonnaise should be stored in the fridge. Homemade mayo should also be stored in the fridge after it’s made.

Refrigerating commercially made mayonnaise will keep it safe to eat for about two months after the jar has been opened. So, if you have a jar of mayo that has been in the back of the fridge for a while, it may not be safe to eat anymore.

As for homemade mayo, it can go bad in the fridge much quicker, lasting at most a week if made with unpasteurized eggs. If you do use pasteurized eggs or a recipe that includes heating the egg mixture, it can last about a month when stored in the fridge.

Does Unopened Mayonnaise Go Bad?

Unopened, store-bought mayonnaise may have a longer shelf-life than opened or homemade mayonnaise, but does mayonnaise go bad when it’s unopened? It can, however, when properly stored, it can last a few months.

At room temperature, unopened mayonnaise can last about three to four months. After this date, the mayonnaise may still be safe to eat but might not have the best texture or flavor quality. Longer than four months is when mayonnaise can go bad and become unsafe to eat. Generally, it's safest to throw mayonnaise away if the best-by date has passed. If it has an expiration instead of a best-by date, you must throw it away once the date has passed to avoid illness.

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Does Mayonnaise Spoil if Left Out?

Once opened, mayonnaise should be refrigerated in order to be safe to eat. But you may forget to put it back in the fridge after spreading it on bread or you may be so wrapped up in cooking that it sits on the counter for a little bit. So, does mayonnaise go bad if left out for a short period of time? If you’re not careful, it can. Opened jars of mayo should not be left at room temperature for more than two hours.

Does Kewpie Mayo Expire?

Kewpie Mayonnaise is a popular brand that is beloved for its rich flavor and creamy texture. However, Kewpie Mayo is still subject to spoiling, just like other brands. It has egg yolks as an ingredient, which means that it can spoil or have a flavor or texture change if left unrefrigerated.

It is suggested by the brand to keep opened Kewpie Mayonnaise refrigerated to prevent the condiment from going bad quicker than it should. It stays good for about a month to two in the refrigerator once opened. In general, Kewpie Mayo will last a year unopened if stored in a cool and dark place like a pantry.

How Long Does Mayonnaise Last After the Expiration Date?

Because of the ingredients, mayonnaise does go bad. However, how long after the expiration date are you able to eat the condiment? For safety reasons, it’s suggested not to eat mayonnaise after the expiration date on the jar.

Unopened jars of mayo that have been sitting in the pantry should be thrown out once it is a week past their best-by date. Opened jars, when refrigerated, should be thrown out by the one-month mark past its best-by date. However, if uncertain, it's recommended that you throw the product out if the best-by date has gone.

While the best-by date may be a little flexible, the expiration date is not. If a jar of mayo has an expiration date, you should not eat it if the date has passed and discard it to prevent any potential foodborne illness.

How To Tell if Mayonnaise Is Bad

Now that we’ve answered the question: “Does mayonnaise go bad?” you may want to know how to tell if it has gone bad. Luckily, it can be relatively easy to tell if mayonnaise has gone bad. Of course, you should also heed the best-by and expiration dates. However, there are sensory signs to be aware of as well. First, if the mayonnaise has begun to discolor and change into a darker shade of white or a brownish-yellow, that may be a sign that the mayo has gone bad.

If the oil has separated, that is also a sign that the condiment is no longer good to eat. Other changes in texture, such as thickness or lumps, are also a sign of bad mayonnaise. Expired mayo additionally tends to have a bad smell, often smelling acidic or putrid. You can give your mayo a sniff and if it has a strong odor, you’ll know that the mayo has gone bad and it needs to be disposed of.

Of course, if you open the jar and see mold or mold spores anywhere inside, that is a telltale sign that you should discard the condiment. If, somehow, you don’t detect any of these signs that your mayo has gone bad and you use it only for it to taste off, that is also a sign of the mayo being bad or at least turning bad. Knowing these signs can protect you from foodborne illness or, at the very least, a badly upset stomach.

Can You Eat Expired Mayonnaise?

Many people often see the date on the jar as a suggestion or at least that you can enjoy the food a few days past it. However, mayo is a little different. So, can you eat mayonnaise past the expiration date? Most experts would say no, that you shouldn’t. Expired mayo is more likely to have harmful bacteria in it. The longer it is past the expiration date or best-by date, the more bacterial growth is likely.

Eating mayonnaise that has gone bad can lead to food poisoning, with symptoms such as stomach pain or cramps, nausea, vomiting or diarrhea. Mayonnaise that has not been refrigerated or has sat outside the fridge for extended periods of time is also at a higher risk of causing food poisoning.

This rule of thumb for not eating mayo that has gone bad applies to food made with mayo as well, such as sandwiches or potato salad. Similarly, if these foods or jars of mayo have sat out, especially in the heat, you should consider it expired and not eat it.

Mayo is a great condiment that can be used as an ingredient in some of your favorite foods and to add flavor and moisture to a sandwich. But does mayonnaise go bad? It does, and mayo is a food whose expiration date must be taken seriously. Specifically, the egg in mayonnaise can cause issues once the condiment is past the expiration or best-by date.

In order to safely enjoy mayo, it’s important to learn how to properly store the condiment and know when is the right time to throw it out. Generally, if you think it has gone bad or if the best-by date has passed, throw it out and buy or make a new batch.

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