Mayonnaise is a must-have ingredient in recipes around the world, but does mayo go bad? Whether you’re using store-bought mayo or making a homemade batch, proper storage is key to maintaining flavor, freshness, and food safety.
The short answer: Yes, mayonnaise can go bad, but its shelf life depends on whether you’re using store-bought or homemade, how it’s stored, and exposure to air and bacteria.
Unopened store-bought mayo lasts up to a year, while opened mayo should be refrigerated and used within 2–3 months.
Homemade mayo, which lacks preservatives, should be refrigerated immediately and consumed within 5–7 days.
Signs of spoiled mayo include mold, sour smell, separation, and discoloration. Proper storage—keeping the lid tightly sealed, refrigerating after opening, and using clean utensils—helps extend freshness.
In this guide, we’ll cover:
- How long mayo lasts
- Signs of spoilage
- When to toss it
- Best storage practices for homemade vs. store-bought mayo
For official food safety guidelines, check the USDA’s recommendations and FDA’s refrigerator storage chart.
Can Mayonnaise Expire?
Yes, mayonnaise can go bad, but its shelf life depends on ingredients, storage conditions, and whether it’s homemade or store-bought.
How Long Does Store-Bought Mayo Last?
Unopened: Up to 1 year in a cool, dry pantry.
Opened (Refrigerated): 2–3 months for best quality.
Opened (Room Temperature): 1 month max, but flavor may degrade faster.
How Long Does Homemade Mayonnaise Last?
Refrigerated: 5–7 days in an airtight container.
Frozen: Up to 3 months, though texture may change.
For official food storage guidelines, you can check the USDA’s recommendations here.
Signs Your Mayo Has Gone Bad
Yes, even refrigerated mayo can spoil.
Here are some warning signs to watch (and do sniff test) for:
- Mold or discoloration (especially around the lid).
- Off-putting smell (sour or rancid).
- Separation of ingredients (excessive wateriness).
- Unusual taste (bitter or overly acidic).
If you notice any of these, discard the mayo immediately.
How Does it Spoil?
Mayonnaise, like any condiment, can spoil over time from exposure to air, moisture, and bacteria. While its high acidity and fat content help preserve it, improper storage can lead to spoilage.
Oxidation: Once you open the jar and it’s exposed to air, it can cause ingredients to break down and change flavor.
Bacterial Growth: If contaminated (e.g., using a dirty spoon), bacteria can multiply, leading to spoilage.
Moisture Exposure: Excess moisture can dilute preservatives, making the mayo more susceptible to mold.
Temperature Fluctuations: Leaving mayo out for extended periods can speed up spoilage.
Which Ingredients in Mayo Go Bad?
Mayonnaise is an emulsion of oil, egg yolks, vinegar (sometimes lemon juice), and seasonings, but some ingredients spoil faster than others. Here’s how:
1. Egg Yolks
Raw egg yolks in homemade mayo are highly perishable and can harbor Salmonella if not refrigerated.
Pasteurized eggs in store-bought mayo last longer but still degrade.
2. Oil
Oils can turn rancid because of oxidation, especially if exposed to air or heat.
Vegetable oils (like soybean or canola) last longer than olive oil, which has a shorter shelf life.
You can recognize this because some rancid oils become bitter and may also have an old waxy smell and/or taste.
3. Vinegar & Lemon Juice
These acidic ingredients help preserve mayo (or any food) by slowing bacterial growth.
However, if diluted (e.g., mixed with other ingredients), their preservative effect weakens.
4. Preservatives (Store-Bought Mayo Only)
- Calcium disodium EDTA and potassium sorbate extend shelf life.
- If mayo is exposed to moisture or heat, preservatives may lose effectiveness.
5. Added Ingredients (Flavored Mayo)
Garlic, herbs, and spices can introduce moisture, increasing spoilage risk.
Dairy-based mayo (like ranch-style) spoils faster than traditional mayo.
Proper storage reduces oxidation and bacterial growth, ensuring mayo stays fresh longer.
How to Prevent Mayo from Spoiling
- Store in an airtight container to limit air exposure.
- Refrigerate after opening to slow bacterial growth.
- Use clean utensils if dipping into the jar to prevent contamination.
- Check expiration dates and discard mayo past its shelf life.
Storing your mayo properly will ensure it remains safe, flavorful, and ready for your next recipe!
See also
Kitchen Tip: Check these other ultimate guides if you’re also wondering how to store other pantry staples like BBQ Sauce, ketchup, molasses, peanut butter, honey and mustard.
FAQ: Does Mayo Go Bad?
1. Do I need to refrigerate mayonnaise?
Yes. You should refrigerate store-bought mayo after opening to maintain freshness. Your homemade batches should always be refrigerated since they lack preservatives and contain raw egg yolks that haven’t been pasteurized.
2. Can I store mayo at room temperature after opening?
You can keep it at room temperature for up to a month, but refrigerate for long-term freshness.
Homemade mayo should always be refrigerated.
3. What ingredients help mayo last longer?
Vinegar & Oil: Both are natural preservatives that slows bacterial growth.
Lemon Juice: Adds acidity, which prevents spoilage.
Salt & Sugar: Help extend shelf life.
4. How can I tell if my mayo has gone bad?
Mold or odd colors (especially around the lid).
Sour or rancid smell.
Separation of ingredients (excessive wateriness).
Unusual taste (bitter or overly acidic).
5. Can I freeze mayonnaise?
Yes, you can freeze mayo, but it’s not recommended. Freezing can extend shelf life up to 3 months, but its ingredients can separate and resulting in a texture change that may not be appetizing.
Store in freezer-safe containers for best results. Thaw overnight and stir well to restore consistency.
7. Does mayo ever expire?
Yes. Even store-bought mayo has an expiration date, though it may still be safe to eat beyond that if stored properly. Always check for signs of spoilage before consuming.
8. Any official food safety guidelines for storage?
The FDA and USDA don’t have mayo-specific guidelines.
But they recommend refrigerating homemade sauces to prevent bacterial growth.
You can check their general food storage recommendations at:
USDA Shelf-Stable Food Guidelines
FDA Refrigerator and Freezer Storage Chart
Final Thoughts: Does Mayo Go Bad?
✔ Your store-bought mayonnaise can last 1 year unopened, but you should refrigerate after opening.
✔ Always refrigerate homemade mayo and use within 5–7 days.
✔ Proper storage ensures longer shelf life, better taste, and food safety.
Further Reading
Does BBQ Sauce Need to Be Refrigerated?
Does Ketchup Go Bad? Everything You Need to Know.
Should Mustard Be Refrigerated?
Does Peanut Butter Go Bad?
Should Soy Sauce Be Refrigerated?
Should Honey Be Refrigerated?
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