- How long does an unopened package of mayonnaise last? The precise answer depends to a large extent on storage conditions -to maximize shelf life, store in a cool, dry area.
How long does an unopened package of mayonnaise last at room temperature? Properly stored, an unopened package of mayonnaise will generally stay at best quality for about 3 to 4 months after the date on the package.
Is unopened mayonnaise safe to use after the "expiration date" on the package? Yes, provided it is properly stored and the package is undamaged - commercially packaged mayonnaise will typically carry a "Best By," "Best if Used By," "Best Before", or "Best When Used By" date but this is not a safety date, it is the manufacturer's estimate of how long the mayonnaise will remain at peak quality.
Storage time shown is for best quality only - after that, the mayonnaise's texture, color or flavor may change, but in most cases, it will still be safe to consume if it has been stored properly, the package is undamaged, and there are no signs of spoilage (see below).
How can you tell if mayonnaise is bad or spoiled? The best way is to smell and look at the mayonnaise: if mayonnaise develops an off odor, flavor or appearance, or if mold appears, it should be discarded.
Sources: For details about data sources used for food storage information, please click here