Last updated: June 10, 2026.
Mayo-based foods should not sit out for more than 2 hours, or more than 1 hour when the temperature is above 90 degrees F. Commercial mayonnaise is acidic, but opened mayo and dishes like potato salad, tuna salad, egg salad, and sandwiches still need safe handling because other ingredients are perishable.
Mayo Safety Table
| Food | Room-temperature rule | Storage note |
|---|---|---|
| Opened jar of mayo | Do not leave out for long serving periods | Refrigerate after opening unless label says otherwise |
| Potato salad or pasta salad | 2 hours max; 1 hour above 90 degrees F | Keep chilled in a cooler or refrigerator |
| Tuna, chicken, or egg salad | 2 hours max; 1 hour above 90 degrees F | Discard if left out too long |
| Sandwich with mayo and meat/egg/cheese | 2 hours max; 1 hour above 90 degrees F | The filling makes it perishable |
| Unopened shelf-stable mayo | Follow the package | Store as labeled before opening |
When To Throw Mayo Away
- It was left out past the 2-hour rule, or past 1 hour above 90 degrees F.
- The jar smells sour, rotten, or yeasty.
- You see mold, separation that looks unusual, or a damaged lid or jar.
- A spoon with food crumbs or saliva was dipped into the jar.
- You do not know how long a mayo-based dish was sitting out.
Serving Mayo-Based Foods Safely
Keep salads and sandwiches cold until serving. For picnics and cookouts, use a cooler with ice packs, serve smaller portions, and refill from the refrigerator instead of leaving one large bowl out for hours.
FAQ
Is mayonnaise safe at room temperature?
Unopened shelf-stable mayonnaise follows its label, but opened mayo and mayo-based dishes should not sit out for long serving periods.
Can mayo sit out overnight?
No. Discard mayo-based dishes or opened mayo that sat out overnight. Do not taste it to check.
Does mayo make potato salad spoil faster?
The whole dish is perishable because it contains cooked potatoes and often eggs, dairy, vegetables, meat, or seafood. Keep it cold and follow the 2-hour rule.
How do you keep mayo safe at a picnic?
Keep mayo-based foods in a cooler or refrigerator, serve small portions, and discard food that has been out too long, especially in hot weather.