Does Mayonnaise Need to Be Refrigerated? [+5 Storage Tips]

Not sure whether you should refrigerate mayonnaise or not? Does mayo need to be refrigerated?

Here’s everything you need to know about storing mayo, no matter if it’s a mayo jar or packet.

Let’s dive right in.

Does Mayo Need to Be Refrigerated?

You can store unopened mayonnaise at room temperature. Once opened, move the mayonnaise to the fridge and make sure it’s always sealed when not in use.

Unopened commercial mayonnaise is perfectly safe at room temperature. A cool and dry place is all it needs to keep for months (here’s how long mayo lasts).

Once you open the mayonnaise jar, you should refrigerate the leftovers, says the University of Wisconsin. This way, they last much longer than if you’d leave the leftover mayo on the counter. The same is true for most (salad dressings)[link how long do salad dressings last].

Mayonnaise Packets

Mayo packets don’t require refrigeration. They easily retain quality for at least a few months beyond the best-by date printed on the label as long as they aren’t exposed to warm temperatures.

In other words, you can carry them while backpacking or on any other type of long trip, as long as you don’t leave them in the sun for too long. They have a long shelf life, making them perfect candidates for that.

If there’s a mayonnaise packet in your backpack and you’re not sure how long it’s been there, open it up and check its quality before using it. My article on the shelf life and spoilage of mayo covers the spoilage signs in detail, but the short version is that you should give it a whiff and look for separation or mold.

Does Mayo Go Bad if Left Out?

The official USDA recommendation is to toss perishable foods, such as open mayo, if they’ve been left out at room temperature for more than 2 hours. That said, your store-bought mayo probably won’t show any signs of spoilage, such as an off smell or oil separation, even if it sits on the counter for a few days.

My advice is simple: if your mayo has been sitting on the counter for a few hours, it’s probably okay. But if you leave it out overnight or longer, it’s best to assume it’s bad and discard it. Better safe than sorry.

Storage Tips

Here are a couple of things to remember about storing mayo:

• Store unopened commercial mayo in a cool, dry place away from heat sources, or refrigerate it. Always refrigerate homemade mayo.
• Refrigerate opened mayonnaise and seal it tightly. Unlike ketchup or chili sauce, leaving opened mayo at room temperature is a bad idea.
• Use clean utensils when handling mayo. A dirty spoon is the easiest way to cross-contaminate your mayo, accelerate bacterial growth, and make the condiment go bad prematurely. Don’t risk food poisoning.
• Write the opening date on the label if you use mayo only once in a blue moon. It’s the easiest way to track how long the jar has been opened.
• Any dishes with mayo, say your potato salad, should be refrigerated.