Does Mayonnaise Go Bad?

So there’s a jar of mayo sitting in your fridge for a few months already. You were about to use it but noticed that it’s past the date on the label. That brings the question: does mayonnaise go bad? Many people think that mayo is very similar in terms of storage and shelf life to ketchup or mustard. There are some similarities, but since mayo contains eggs, there are some significant differences too. In this article, we will go through storage, shelf life, and going bad of mayo. If you’d like to learn a bit more about this condiment, read on.

Mayonaise
(credit: fotoosvanrobin)

How To Store Mayonnaise

For an unopened jar of mayo, storage guidelines are pretty much the same as for mustard. That means you should keep it at cold temperature, in a dry place away from sources of heat. A cabinet in the kitchen that’s away from the oven is a popular choice, but the pantry works well too. Unopened mayo doesn’t require refrigerating, but of course, keeping it in the fridge won’t hurt either.

Once you open the jar, keep it tightly sealed in the fridge when not in use. Unlike ketchup or BBQ sauce, open mayo shouldn’t be stored at room temperature. Same thing with any sandwiches or dishes with mayo.

When it comes to homemade mayo, you should always keep it in the fridge.

Last but not least, let’s talk a bit about food hygiene. You should always scoop mayo with clean utensils used only for that mayo. If you’re using the same ones you use for other food products, you’re risking cross-contamination. “Double-dipping” may transfer some harmful bacteria into your mayo, and that will cause it to go bad much sooner than you’d like. If your mayonnaise comes in a squeeze bottle, make sure you clean it with a dry paper towel, not a wet one.

How Long Does Mayonnaise Last

Pretty much all jars of mayo come with a best-by date. That date is an estimate for how long the product will retain its freshness. That means that the product will probably last longer. How long exactly will it last past the best-by date?

Unfortunately, it’s impossible to tell. It’s even difficult to give a rough estimate at this point. That’s because there are hundreds of mayos produced by various companies and each one with its own unique ingredients list. Some of them, like the Hellmann’s Real Mayo, use mostly simple ingredients, like oil, eggs, vinegar, and some condiments. Others add a bunch of preservatives to the mix, which makes the mayo last months or even years in the fridge, but isn’t very beneficial to one’s health. To simplify, we can assume that the mayo should be okay for about 2 to 3 months after the best by date.

When it comes to homemade mayo, it should last about a week in the fridge. If you wonder why your homemade mayo doesn’t last as long as a store-bought one with the same ingredients, the answer is simple. The mayo you make on your own is most likely made using raw eggs. Commercial mayonnaise uses pasteurized eggs, which are both safer (in terms of food safety) and last longer.

Pantry Fridge
Mayonnaise (unopened) Best by + 3 – 4 months
Mayonnaise (opened) Best by + 2 months
Mayonnaise (homemade) 1 week

Please note that the periods above are estimates and for best quality only.

How To Tell If Mayonnaise Is Bad

There are at least a few symptoms that your mayo has gone bad. Here they are:

  • Any organic growths inside the jar, like mold or spores.
  • Off, acidic, or putrid smell.
  • Noticeable change of color, like darker shade of white or brownish yellow.
  • Off taste.

If you notice any of the symptoms above, discard the mayo. Same thing if you’re storing it for a very long time, even if it seems perfectly fine. Better safe than sorry.