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!
Without refrigeration: no more than a couple hours.
With refrigeration: should be consumed the day it is made - the mayo will eventually get absorbed into the bread and make it very soggy.
A couple minutes if my kid is around...
Mayonnaise is not likely to be what gives you the food poisoning. It is common to see it left out at room temperature in some countries. It is the fish that will feed the bacteria and make you sick. If it is a hot day, you may find yourself with a case of food poisoning after eating a tuna sandwich that has been sitting out warm for an hour.
A sandwich with mayo can last a long time. Since I was five, I carried lunch in a Karo Syrup bucket, later a kraft brown bag, and left it in my saddle bag, or locker, or in the car for many hours (even days). The sandwich was always there; nothing happened to the sandwich and I eventually ate it. Of course, sometimes the bologna curled, the chicken dried out (wrapped in wax paper), the garden leaf lettuce always withered and got a little slick, but the mayo . . . the mayo never seemed to change. I am past eighty and have been told for nearly eight decades that I will die of food poisoning. Perhaps.
We dassn't throw food away. We ate it. Maybe, we are already poison. They say Grandpa was riding our pasture along the Scottsbluffs, a big rattler bit him and the poor thing died. I didn't know Old man Strickland but if they had mayo in his day, my guess he probably didn't cold-store his sanny either.
It should last at least a day I make them the night before put them in the fridge then take them to school the next day and it's all fine!!
Foods containing mayonnaise should be good for 3 - 5 days if stored in the refrigerator.
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
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.
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.
Ham, American Cheese, and Mayo
mayo, tomatoes, lettece, mustard.
chicken cutlet sandwich with mayo