Onions are useful pantry staples, but different types need different storage conditions. So, can onions go bad?
Yes, onions can go bad. How long they keep depends on their type, condition, and storage. Whole, cured storage onions keep well in cool, dry conditions with good airflow. Whole sweet onions and green onions benefit from refrigeration, while peeled, cut, and home-cooked onions need to be kept refrigerated.
Let’s dig deeper into this now.
How Long Do Onions Last?
Whole, properly cured storage onions can keep for several weeks or longer in suitable conditions. Their variety, condition, and storage environment affect how well they keep.
Store them in a cool, dry, dark place with good airflow, and buy an amount you can use while the bulbs are in good condition.
How long an onion lasts depends on the type of onion, whether it’s cut or whole, and how you store it.
For whole, cured storage onions, use a dry basket or breathable bag that allows air to circulate.
Exposure to moisture can cause mold formation on the surface and lead to spoiling.
Once you peel or cut an onion, put it in a clean, sealed container in the refrigerator. Colorado State University Extension recommends using peeled or cut onions within seven days.
Keep the refrigerator at 40°F (4°C) or below. Refrigerate cut onions within two hours, or within one hour if the air temperature is above 90°F (32°C). Discard them if they have been left out longer.
How Do You Know If An Onion Has Gone Bad?
For good quality, choose firm bulb onions with dry, papery skins and no bruises or visible decay.
The firm flesh lies in layers beneath the dry outer skin.
Onions with cuts and bruises are prone to rotting. They may produce moldy patches or become soft.
Leaving such rotting onions with the rest of the batch increases their chances of spoiling too.
Discard moldy, slimy, or rotting onions and keep them separate from the sound bulbs.
The onions you store in your pantry or countertop have a long shelf life but will not last forever.
Unless you use them up quickly, they will start spoiling.
As onions spoil, their skin becomes soft and mushy.
It will yield to your touch and may even have moldy patches on the surface.
Sprouting alone is a change in quality rather than proof of rot. Purdue Extension notes that the firm flesh can still be used, but a sprouting onion should be used promptly. Discard it if it is moldy or rotting.
Normal appearance and smell cannot prove safety. Follow the storage and handling guidance for the type of onion you are using.
Once rotting sets in, onions turn slimy and emit foul odors that stink up the entire kitchen.
They will also release smelly liquids that stain surfaces. Get rid of the onion before it reaches this stage.
Can Onions Go Bad In The Fridge?
Yes. Onions can still spoil in the refrigerator, so the storage method should match the type of onion and whether it is whole, peeled, or cut.
Whole sweet onions can be kept unpeeled in the refrigerator. Wrap each bulb in a dry paper towel and place it in the crisper drawer to help manage moisture.
Keep peeled or cut onions in a sealed container and use them within seven days. This follows Iowa State University Extension’s guidance for cut onions and the peeled-onion guidance above.
For the differences between whole storage onions, sweet onions, and prepared onions, see the onion refrigeration guide.
For longer storage, freeze freshly prepared chopped onions in freezer-safe bags or containers. Frozen onions work well in cooked dishes such as soups and casseroles.
Can Pickled Onions Go Bad?
Yes, pickled onions can go bad. How you store them depends on whether they are refrigerator pickles, home-canned onions, or a commercially packaged product.
If you make quick pickled onions that are meant for the refrigerator, keep them at 40°F (4°C) or below. Follow a reliable recipe and its storage instructions, including how soon to use the onions.
Vacuum-sealing a jar by itself does not make pickled onions safe to store in the pantry.
For home-canned pickled onions that you want to store in the pantry, follow a tested canning recipe for that product. The National Center for Home Food Preservation recommends using tested ingredient proportions and the correct processing procedure.
Store properly processed, sealed home-canned jars in a cool, dry, dark place. Refrigerate the onions once you open the jar and follow the recipe’s storage guidance.
For store-bought pickled onions, follow the label’s storage directions before and after opening. Check for instructions to keep the jar refrigerated and for any time limit on using the onions after opening.
A ‘best if used by’ date refers to quality. Keep following the storage directions even when the date is still in the future.
Discard pickled onions that show mold or other signs of spoilage without tasting them. If a home-canned jar is leaking or bulging, or you are unsure whether it was prepared and stored safely, follow the NCHFP’s guidance for handling and disposing of suspect jars.
Can Green Onions Go Bad?
Green onions do not keep as long as cured storage onions.
The green leafy bits spoil quickly, so you should store these onions in the refrigerator.
Plan to use green onions within about a week, following Purdue Extension’s storage guidance.
Place them in a plastic bag with a damp paper towel and keep them in the refrigerator.
Do not use leaves that have shriveled or turned yellow.
Discard green onions that are slimy, moldy or rotting.
Can White Onions Go Bad?
Whole, cured white storage onions can keep for several weeks, but they will eventually deteriorate.
Keep them in a cool, dry, dark place with good airflow, such as an open basket or mesh bag.
How long they keep depends on their variety, their condition when you buy them, and the storage conditions.
Check for soft, rotting areas, mold or unusual wetness around the neck of the bulb.
Discard bulbs that are rotting or moldy.
Some white onions begin sprouting when left untouched for too long.
Sprouting alone does not mean an onion is rotten. Purdue Extension says you can still use the firm flesh, but the bulb deteriorates faster, so use it promptly.
Can Yellow Onions Go Bad?
Yellow onions sold as cured storage onions can keep well, just like white and red storage onions.
When stored properly, whole and unpeeled yellow storage onions can last several weeks.
Keep them in a cool, dry, dark place with good airflow. UMass Extension suggests using whole yellow, white and red onions within six weeks for best quality; this is a guide, not a promise that every bulb will last that long.
Nevertheless, yellow onions will eventually spoil.
Check stored bulbs regularly for mold or rotting flesh. Sprouting is different from rot, as explained above.
Exposure to moisture will increase the rate at which they will spoil.
It’s important to discard a yellow onion as soon as it begins to show signs of spoilage.
Whole sweet onions can benefit from refrigeration, while cured storage onions keep well in a cool, dry, ventilated place.
You do not need to remove the papery skin just to refrigerate a whole onion.
Once an onion has been peeled or cut, keep it in a sealed container in the refrigerator at 40°F (4°C) or below.
Use whole peeled onions within seven days, following Colorado State University Extension’s guidance. Iowa State Extension recommends the same seven-day limit for cut onions.
Can Fried Onions Go Bad?
For homemade fried onions, follow the same storage rules as other cooked leftovers.
Refrigerate them within two hours of cooking, or within one hour if the air temperature is above 90°F (32°C). Discard them if they have been left out longer.
Use shallow, covered containers so that they cool quickly, and keep the refrigerator at 40°F (4°C) or below.
Use refrigerated fried onions within three to four days, following the USDA’s guidance for cooked leftovers.
Discard refrigerated leftovers after this period, even if they look and smell normal.
If you want to keep them longer, freeze them promptly. Aim to use frozen cooked onions within three to four months for best quality.
For store-bought crispy onion toppings, check the storage instructions on the package.
Follow the after-opening directions; do not assume that every product needs refrigeration or freezing.
Can Caramelized Onions Go Bad?
Caramelized onions need the same care as other cooked leftovers.
Refrigerate them within two hours, or within one hour when the air temperature is above 90°F (32°C).
Keep them in a covered container at 40°F (4°C) or below, and use them within three to four days.
You can also freeze caramelized onions in a good airtight container or bag to prolong their lifespan.
The three-to-four-month freezer guide is about quality. Cooked onions that were handled safely and stay frozen at 0°F (-18°C) or below remain safe longer, although their quality declines. Freezing does not make unsafe food safe.
