How Long Does Mayo Last in the Fridge?

mayonnaise shouldn’t be left sitting at room temperature indefinitely.

According to USDA food-safety guidance, perishable foods should not remain in the 40°F–140°F (4°C–60°C) danger zone for extended periods.

The general rule is to refrigerate perishable foods within two hours, or within one hour when temperatures are above 90°F (32°C).

That matters especially at picnics, barbecues, parties, and outdoor gatherings.

If a mayonnaise-based salad or sandwich has been sitting outside in hot weather for several hours, don’t assume putting it back in the refrigerator will make it safe again.
Why Does Mayo Need Refrigeration After Opening?

Commercial mayonnaise is formulated to