How to tell if mayo is bad.

How to Tell If Mayo Is Bad or Still Good to Eat

You’re in the kitchen, mayo jar in hand, wondering: “Is this still okay?” If you’ve thought this, you’re not alone. Today, we’re tackling a common question: “How to Tell If Mayo Is Bad.”

According to the USDA, if your mayo jar is unopened, you can keep it in the pantry. But after you open it, make sure to put it in the fridge and aim to use it within 2 months. If you’re not sure how long it’s been since you opened it, we’re here to help.

Whether you bought it at the store or made it at home, we’ll explain how long it usually lasts and how to spot if it’s gone bad. Ready to learn about mayo? Let’s go.

How to Tell If Mayo Is Bad

When it comes to mayonnaise, subtle hints often reveal its true state. Let’s pinpoint the exact symptoms that signal it’s time to let go of that mayo.

Related: How Long Does Coleslaw Last? Understanding Coleslaw Shelf

Organic Growths Inside the Jar

The first red flag? Any sort of organic growths like mold or spores. Always check the top layer inside the jar and along the outside too. If you even spot the tiniest mold, especially green, blue, or black spores, it’s a no-go. It’s safer to toss the mayo out.

Color Changes: Yellow or Brown Hues

Your mayo should be a consistent off-white shade. If you’re seeing a yellow tint or even a brownish discoloration, it’s a sure sign that it’s past its prime. Before using, always inspect the jar’s contents.

Unpleasant Odor: Acidic or Putrid Smells

While fresh mayonnaise typically has a mild scent, spoiled mayo will be quick to show its true colors (or scents!). If you’re hit with a strong sour or acidic odor upon opening the jar, don’t second-guess—safely discard it.

Taste Differences: Bitter or Sour Notes

While we don’t advocate tasting something you suspect has gone bad, sometimes a quick taste test is all you need. If your mayo tastes strange, especially if it has sour or bitter undertones, it’s time to say goodbye.

In the grand scheme of things, it’s always best to be cautious. If your mayo displays any of these symptoms, or if you’ve stored it for an unusually long time, it’s wiser to let go. After all, when it comes to food, it’s always better to be safe than sorry.

How Long Does Mayo Last?

Mayonnaise stands apart from many other condiments, primarily because of its perishable egg yolk content. Let’s break down its shelf life based on various scenarios and storage methods.

  1. Unopened Commercial Mayo: A store-bought mayo jar remains safe for use for about 2 to 3 months beyond its “best by” date when stored in a cool, dry place. The “best by” date signifies the period up to which the mayo retains its optimal flavor and texture. Preservatives present in commercial mayo, along with egg yolks, play a critical role in this timeline.
  2. Opened Commercial Mayo in the Fridge: Post its initial introduction to the outside world, the mayo’s longevity reduces. It’s advised to consume it within roughly 2 months, provided it’s continually stored in the refrigerator. Since most mayo formulations include egg yolks, refrigeration becomes vital to keep spoilage at bay and ensure it stays preserved.
  3. Homemade Mayo: If you’re into crafting your own mayo, you should know it has a shorter shelf life due to the absence of commercial preservatives. Some culinary aficionados vouch for its use within just 2 to 3 days, while others believe it can stretch up to a week when refrigerated. To be on the safer side, using it within a week is a good rule of thumb.
  4. Mayo on the Counter: An opened mayo jar left outside for over 8 hours is inviting unwanted bacterial guests. The egg yolks, being perishable, make mayo vulnerable. Therefore, always ensure you place it back in the fridge soon after usage.
  5. Mayo in the Freezer: While it’s possible to freeze mayo before its “best by” date, expect some changes upon thawing. The consistency becomes watery, and the color might shift to a more yellowish hue. This change isn’t indicative of spoilage. Rather, the mayo’s acidic components and oil undergo separation at freezing temperatures, leading to this altered appearance.
Storage SituationShelf LifeAdditional Info
Unopened Commercial Mayo2 to 3 months past “best by” dateStored in a cool, dry place. “Best by” indicates optimal flavor and texture.
Opened Commercial Mayo in the FridgeAbout 2 monthsAlways keep in the refrigerator due to egg yolk content.
Homemade Mayo2 to 3 days to 1 weekShorter shelf life due to lack of commercial preservatives.
Mayo on the CounterNo more than 8 hoursReturn to fridge promptly after use.
Mayo in the FreezerCan be frozen before “best by” dateConsistency changes upon thawing; expect a watery, yellowish appearance.

How to Store Mayonnaise the Right Way

For unopened mayo, keep it in a cool, dry place, like a pantry or a kitchen cabinet away from heat. Although commercially made mayo has preservatives that ward off bacteria, consider refrigerating it for longer shelf life—up to a year.

Once opened, always refrigerate due to its raw egg content. Homemade mayo? Consume within a week and store in a tight container in the fridge.

Tips on Storing Mayo

  1. Utensils Matter: Always use clean utensils for scooping mayo to avoid cross-contamination. The last thing you want is bacteria from other foods getting into your mayo jar.
  2. No Double Dipping: This can introduce harmful bacteria, making the mayo go bad faster. If your mayo comes in a squeeze bottle, a quick wipe with a dry paper towel after use keeps it clean.
  3. Monitor Dates: While the “Best By” date on the packaging is a helpful indicator, always trust your senses first. If it looks or smells off, better to be safe than sorry.
  4. Room Temperature Caution: If mayo is left out for over two hours at room temperature, or just an hour in temperatures above 90°F (32°C), it’s best to discard it. Safety first!
  5. Avoid Freezing or Microwaving: Mayo doesn’t take well to freezing, and you shouldn’t microwave it to bring it to room temperature.

Frequently Asked Questions

Let’s address some common questions related to “how to tell if mayo is bad”.

How do you know if mayonnaise goes bad?

Mayonnaise can show several signs of spoilage:

  • Texture Changes: It may become separated, with water on top or become overly thick.
  • Discoloration: Fresh mayo is off-white. If it turns yellow or brownish, it’s likely spoiled.
  • Off Smell: Fresh mayo has a subtle tangy scent. A rancid, acidic, or putrid smell indicates spoilage.
  • Presence of Mold: Any mold or spores, especially green, blue, or black ones, are a definite sign of spoilage.
  • Sour or Off Taste: If it tastes unusual, it’s best to discard it.

What can happen if you eat bad mayonnaise?

Consuming spoiled mayonnaise can lead to food poisoning. Symptoms might include stomach cramps, diarrhea, nausea, vomiting, and fever. Since mayo contains raw eggs, there’s also a risk of salmonella contamination.

Can mayo go bad in the fridge?

Yes, even in the fridge, mayo can go bad. Commercially packaged mayo can last about two months in the fridge after opening, while homemade mayonnaise might only last a week due to the absence of preservatives. Always check for signs of spoilage before consumption.

What does bad mayonnaise smell like?

Bad mayonnaise often gives off a rancid or sour odor, different from its usual mild, tangy aroma. Any strong, unpleasant, or off-putting scent is a sign that the mayo has turned and should not be consumed.


In conclusion, understanding the signs of spoiled mayo and its proper storage can save you from unwanted food mishaps.

By staying informed and attentive, you can ensure every sandwich, salad, or dish benefits from fresh and flavorful mayonnaise. Stay savvy in the kitchen and always prioritize your health and taste buds!

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