If the mayonnaise is unopened it should last about a year, in or out of the fridge. Once you open it you should store it in the fridge. Mayonnaise usually contains vinegar, which helps to preserve it but you should probably finish it before two or three months.
It helps a lot if you do NOT introduce bacteria into the opened jar. So use a clean spoon, and don't lick and stick your fingers in!
look at the expiration date, if its in the jar in the fridge it should last about 2-3 months. if its on a sandwich it should last a few hours, depending on how cool it is. In my opinion mayo can not go bad in 3 to 4 months because of the vinegar that preserves it
Homemade mayonnaise typically lasts for about 1 to 2 weeks when stored in the refrigerator.
Due to the contents of Mayo (mostly the creams and raw eggs), it is hazardous to keep mayo if the jar has gone warm for longer then an hour.
Homemade mayonnaise typically lasts for about 1 to 2 weeks in the refrigerator before it spoils.
His favorite food is a Chicken Cutlet Sandwich with mayonnaise.
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.
Mayo
Assuming the fridge is set at the correct temperature and working correctly, I wouldn't go beyond two days because of the ingredients in the mayonnaise.
TOO Much
mayonnaise
According to "The Association for Dresses and Sauces," commercially available mayonnaise can be left out of the refrigerator for a long time and still be safe. Apparently, the eggs used in commercial mayo are pasteurized, killing bacteria like Salmonella. Also, they say, commercial mayo is sufficiently acidic to be unfavorable to bacteria that may be introduced after opening the jar. I always assumed that Salmonella was the prime problem, but if you think about it, mayo sits on store shelves unrefrigerated for a long time, and there's no reason Salmonella couldn't grow then. TADS also says the reason refrigeration is recommended by the mayo jar is to preserve fresh taste.
chicken cutlet sandwich with mayo