How to Tell If Corn on the Cob Is Bad

Fair to say, almost all of us are familiar with corn. But that doesn't mean it can't be tricky to tell whether corn on the cob is bad, safe to eat or altogether spoiled, depending on the ear of corn you're looking at. Here, we'll tell you how to select the freshest corn and how to store it. Plus, we'll answer those nitpicky questions about mold, worms and oddly sized or missing kernels.

corn on the cob
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Few things are sweeter in the summertime than fresh corn. It's a healthy vegetable that can be enjoyed simply with some butter and salt, or can be turned into fresh griddled tortillas, a cheesy casserole and even fritters.

But unfortunately, corn can turn from sweet and fresh to spoiled more quickly than you might think. Here's how to ensure you're picking the cream of the crop, and what to look out for on your next grocery store run.

How to select corn at the store

Corn will be best enjoyed on the day you purchase it, so picking the freshest available is a must. "At the store or your farmers' market, ask how fresh the corn is. The closer you get it to harvest, the better," advises Rachael Narins, a Los Angeles-based cookbook author and chef-instructor.

Go for ears that are firm to the touch, with moist-looking bright green husks. As for the silk tassels, the hair-like strands sticking out from the top of the corn, they should also look fresh. Some browning at the top is OK, but if they're entirely brown or dried out, put them back.

"If you're selecting unshucked cobs, they should feel heavy, and the kernels should feel plump when gently squeezed. The fresher your corn, the sweeter it will be," says Narins.

Corn that does not exhibit these qualities should be avoided. If it's not in great shape at the store, it will quickly go bad at home, turning soft or mushy with a dried-out husk and fully browned tassel. Withered or dry kernels are another sign your corn has passed its prime.

How long does corn last? How should I store my corn?

Corn isn't something you should pick up early in the week, if you aren't planning to eat it until the weekend. If you can't enjoy it on the day of purchase, though, there's hope to keep it fresh for up to two days:

  • Unshucked: Store your ears loose in the crisper drawer.
  • Shucked: The husks act as a protectant for your corn, so shucked corn is more prone to drying out. It should be in an airtight container or storage bag in your refrigerator.

If you won't get to your corn within a day or two, try freezing it instead. Narins shares, "If you want to preserve a bit of summer, corn freezes well on the cob, or you can cut the kernels off. Place either in a large plastic bag and lay flat in your freezer. It will keep for up to four months."

What if some of my corn kernels are moldy?

The appearance and aroma of your corn are the two main ways to tell whether or not it has gone bad. If it's giving off a rancid or moldy smell, or has a slimy and mushy texture, it should be tossed in your compost. Similarly, if there's any visible mold on your corn, it has gone bad.

But not all fungus is bad, says Narins. "If you notice huitlacoche—a black, mushroom-like fungus growing on the cob—that isn't mold. Consider removing it and using it as a delicious addition to tacos and quesadillas." Huitlacoche is fairly common in Mexican cuisine, especially in that of central Mexico. While not as common in the U.S., it has been gaining popularity for years, through its use by taco vendors and chefs in fine-dining restaurants.

If you notice something funky or unusual on your corn, ask your grocer or farmers' market salesperson about it. They should be able to identify it and tell you whether or not you're dealing with huitlacoche or should just toss the corn in your backyard compost heap.

What if I find a worm in my corn?

If you're getting ready to make dinner only to discover a worm joining you, it's likely a corn earworm. The corn itself is still fine to eat. You can discard the worm and just chop off the area (likely the tip) where it was chowing down, and add it to your compost bin.

What if my corn kernels are irregularly sized or missing?

If you notice some kernels are larger than others, a few kernels are missing or the tip is totally barren, don't sweat it. The corn is still perfectly fine to enjoy; it just wasn't properly pollinated in the growing stage. Each kernel needs to be properly fertilized in order to grow, and if the process is unsuccessful, you may be left with only cob and no corn in some areas.

How to tell if cooked corn is bad

Ideally, you'll catch corn on the cob that has gone bad before cooking, as it can be harder to identify spoilage when dressed in butter or toppings. The same slimy texture and moldy smell that identify fresh corn as being bad can also be signs that your cooked corn has gone bad.

Bottom line

Corn is a hearty crop. At its peak, it should be firm, plump and brightly colored. Slimy, smelly and/or moldy corn is bad. But, if you find a worm, just pick it out. A few missing kernels? Still perfectly edible. Especially during the summer, it's hard to find a more delicious, affordable and simple-to-prepare vegetable.

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