Food expiry database
How Long Does Mayonnaise Last After Opening
FoodKeeper lists commercial mayonnaise as best within 3 to 6 months after the package date in the pantry, or about 2 months in the refrigerator after opening. FoodKeeper also says shelf-stable commercial mayonnaise is safe at room temperature after opening, and that refrigeration after opening is mainly for quality, not safety.
This page is built around the moment the package is opened, because that is usually when the most useful household reminder actually starts.
Quick storage guide
| Situation | How long it usually lasts | Storage | Safety or quality? |
|---|---|---|---|
| Unopened | 3 to 6 months after the package date | pantry | Quality |
| Opened | 2 months | refrigerated after opening | Quality |
| Refrigerated | 2 months after opening | Refrigerator | Quality |
What the source actually supports
- Mayonnaise: 3 to 6 months after the package date in pantry — FSIS FoodKeeper data.
- Mayonnaise after opening: 2 months in refrigerated after opening — FSIS FoodKeeper data.
- For this item, FoodKeeper frames refrigeration after opening as mainly a quality issue, not a safety issue — FSIS FoodKeeper data.
- Warm-exposure decisions can be stricter than everyday storage guidance — see FoodSafety.gov's power outage chart.
What the official after-opening guidance means for mayonnaise
FoodKeeper lists commercial mayonnaise as best within 3 to 6 months after the package date in the pantry, or about 2 months in the refrigerator after opening. FoodKeeper also says shelf-stable commercial mayonnaise is safe at room temperature after opening, and that refrigeration after opening is mainly for quality, not safety.
For mayonnaise, the official window only makes sense when you pair it with how the item was actually stored, handled, and served at home. Warm exposure, repeated opening, contamination, and missing open dates can matter just as much as the printed date.
How to store mayonnaise
For commercial mayonnaise, the practical question is usually quality after opening, not whether the jar becomes instantly unsafe the moment it leaves the pantry. Keep the lid clean, close it tightly, and refrigerate after opening if you want it to stay fresher longer.
What matters more than the pantry-versus-fridge debate is how the jar was handled. A jar that sat out at a cookout or was repeatedly contaminated by dirty utensils should be treated more cautiously than a clean jar kept at home.
Signs mayonnaise should be discarded or replaced
- Discard mayonnaise if the jar is bulging, leaking, or the contents have separated in a way that looks unusual for the product.
- Replace it sooner if it was left out for an extended period during a meal or gathering.
- Do not keep using it if you cannot tell how long the opened jar has been around.
Track the opened item, not just the unopened package
ShelfDate is most useful when fridge and pantry items get an open date, a printed date, and a reminder before they quietly turn into guesswork.
Download Shelf Date if you want the next action view instead of another passive list.
When to set a reminder in ShelfDate
- Track the package date if you buy backup jars.
- Set an open-date reminder on the day you break the seal.
- Add a shorter reminder for summer cookouts, picnics, or power outages where temperature abuse matters more.
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Common questions about mayonnaise
For mayonnaise, the open date and the way the item was handled after opening usually matter as much as the printed package date.
Sources
- FSIS FoodKeeper data — USDA item-level storage data used for Mayonnaise — commercial.
- Food Safety During Power Outage — FoodSafety.gov keep-or-discard backup guidance after unusual warm exposure.