How To Know If Your Mayo Has Expired

When you finally take the time to go through the condiment shelves in your refrigerator, it can be tough to know what to toss and what to keep. While expiration dates are the standard go-to for deciding when it's time to throw away condiments, there are a few other things that you'll want to keep in mind. It's especially important to understand spoilage rules when you're dealing with condiments that spoil faster than others — like mayonnaise. 

Once a jar of mayonnaise is opened, it'll stay good in the fridge for up to two months. Homemade mayo (and homemade aioli) is only good in the fridge for a couple of days, so be sure to use it quickly if you go through the work of whipping up a batch in your kitchen. An important note: If you see a great sale on mayo or other condiments and want to stock up, just be sure to take a look at the expiration date. The two-month rule only applies after mayo is opened, so you'll be able to store unopened containers in your pantry for far longer. There's a restaurant storage tip to help you know how long your mayo has been in the fridge: Simply mark the date you open it on the lid with a permanent marker.

You can't always trust dates, though. Environmental conditions can shorten or lengthen the shelf-life of may. For more of a visual cue as to the quality, there are a few things to keep an eye on.

Whether you choose chef-favorite Kewpie mayo, stick to Julia Child's beloved Hellmann's, or prefer our favorite, Wild Harvest, it's important to keep an eye out for signs of mayo spoilage. While an overly foul smell can certainly be a sign of spoilage, there are a few other signs that you'll want to look for. It can be a little bit tough to tell whether mayo has gone bad, since the vinegar in most mayonnaises can add a bit of a sour smell even when your jar is perfectly fresh. 

Taking a quick look inside your mayo jar can help clue you in as to whether your jar is fresh. Keep an eye out for mold, which often develops faster on the lid than in the jar itself. Be sure to look underneath if you're not seeing signs of mold in the mayo itself, but aren't sure whether it's still good. If you notice that the oil of the mayo is separating from the rest of the ingredients, or a watery layer has appeared on the top of your mayo, don't try to stir it up — it's time to toss it in the trash. To help your mayo stay good in the fridge as long as possible, always use a clean utensil when you're scooping it out of the container. When bits of food get mixed in with your mayo, it's likely to spoil more quickly.