Unopened it will last on the self for a year or more. But once it is opened, it will last a couple of months in the fridge. If you've opened the container or used mayo on a sandwich or in a salad, it shouldn't be left unrefrigerated for more than a couple of hours.
Mayonnaise Spoilage Myths - Mayonnaise Safety http://homecooking.about.com/od/howtocookwithcondiments/a/mayospoilage.htm
A turkey sandwich with mayonnaise should be eaten within three hours if not kept cool. Mayonnaise has a tendency to spoil rather quickly at room temperature.
They don't make cheese with mayonnaise
Once it's opened you do.
You can safely refrigerate mayonnaise for up to two months after opening.
Shut up you troll.
It can, but not for long.
Homemade mayonnaise typically lasts for about 1 week in the refrigerator before it spoils.
You feed it oatmeal, bathe it in ice and sugar, and spread mayonnaise on it.
Homemade mayonnaise is typically good for about 1 week when stored in the refrigerator before it spoils.
The shelf life of mayonnaise is typically around 2 to 3 months when stored in the refrigerator. It is important to check the expiration date on the packaging and discard any mayonnaise that has passed this date to ensure safety.
Homemade mayonnaise typically lasts for about 1 to 2 weeks in the fridge before it spoils.