How to store sliced onions? (+5 health benefits)

In this article, we will answer the question “How to store sliced onions?”, and how to tell if the onion is bad?

How to store sliced onions?

Storing onions for later use is a great way to avoid working with them frequently especially if you find their smell offensive. Chopping onions also leave you all teary and nobody wants that to happen every other day. The ideal temperature to store onions is 40–50°F at moderate humidity.

Sliced or cut onions can be kept in the fridge or even in the freezer for long term storage. Read on if you want to know how to store cut or whole onions at room temperature, in the fridge, and In the freezer.

At room temperature

Whole onions will keep fresh for longer when stored at room temperature. Keep them in a plastic mesh or a woven basket for proper air ventilation. Keep away from light. Moisture and heat will speed up their rotting process. It is not recommended to store cut or sliced onions at room temperature. 

In the fridge

The humid environment of the fridge will spoil the whole onions rapidly. However, it is not the same case for cut or sliced onions. Cut or sliced onions need to be kept in the fridge immediately if they are not to be used soon after cutting.

Stored cut or sliced onions should only be used for cooking. Avoid eating them raw in salad bowls. Wrap a plastic sheet or cling film tightly around the cut onion and keep it in the fridge. Alternatively, you can store them in an air-tight container to minimize oxygen and moisture contact.

In the freezer

Freezing a cut or whole onion is not recommended. Freezing considerably degrades their texture making them mushy. However, storing chopped or sliced onion in the freezer will save you a lot of time. You do not even need to defrost the slices if they are to be cooked. Just toss them directly on the flame and proceed with your recipe.

The shelf-life of onions

In the pantryIn the fridgeIn the freezer
Whole onions1-6 monthsNot recommendedNot recommended
Half-cut onionsNot recommended6-10 daysNot recommended
Chopped or sliced onionsNot recommended6-10 days6-8 motnhs

How to buy onions?

When shopping for yellow and red onions, look for the ones with dry and peppery skin. They should have a firm texture and a considerable weight that shows they are not overripe. The onions should not have soft or mushy areas.

When shopping for spring onions, look for the ones with unbruised and frim stalks. The bulb should not be slimy. Leeks should have crisp and firm stalks with no discoloration.

How to tell if the onion has spoiled?

When exposed to moisture and heat, onions will start to sprout. The bulb will shrink giving rise to the greens on top.

Sliced, cut or whole onions might develop dark or moldy spots on them due to improper storage. In addition to this, sliced or cut onions will develop a slimy texture when spoiled. Whole onions start to become mushy.

Does eating bad onions make you sick?

Eating a bad onion might not have any serious effects. Your stomach might act up a little and obviously, it will taste bad. But food poisoning from eating a bad onion is a rare case.

Health benefits of onions

Rich source of fiber

Onions are rich in fiber especially the soluble fiber called fructans that is considered a prebiotic fiber. They feed the healthy gut bacteria that results in the formation of Short Chain Fatty Acids SCFA, which improve gut health, reduce inflammation, and prevent cancer.

Good source of Vitamins and minerals

Onions are a good source of certain vitamins and minerals like Vitamin C, Vitamin B9 which is also called Folate, vitamin B6 and potassium. Vitamin C has excellent anti-oxidant properties. Folate and Vitamin B6 are essential for metabolism and Erythropoiesis. Potassium helps maintain fluid balance in the body.

Controls blood sugar

Onions have been found to prevent Diabetes type1 and 2 by regulating the blood sugar levels.

Improves bone health

Onions have been linked to promote Bone mineral density and prevent bone deterioration. This helps prevent osteoporosis in older adults.

Contains anti-oxidant compounds

Anthocyanins present in onions act as anti-oxidants and give onions their purple or red color.

Reduces risk of heart diseases

A flavonoid compound, called QUercetin, present in onions control blood pressure and reduces the risk of heart-related disease. 


In this article, we answered the question “How to store sliced onions?”, and how to tell if the onion is bad?


Hello, I'm Sana Ameer. I'm a student of Food Science and Technology at UVAS. I like to bake and I aspire to become a Food blogger.

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