How long do onions last in the fridge?
In this article, we will answer the question “How long do onions last in the fridge?”. We will also discuss how to store onions, what is the shelf life of onions, how to tell when they are bad and if bad onions can make you sick.
How long do onions last in the fridge?
Onions can generally last in the fridge for up to two to three months when stored at 0 to 4°C (32 to 40°F). Since onions are not sensitive to chilling injury, they can be stored at -2 to -3 °C (28 to 27 °F). Storage at temperature below -4 °C (25 °F) may cause freezing injury (1,2).
Fresh cut onions can last for up to 15 days when stored at 0 °C and 85–90% relative humidity, showing less changes in physicochemical aspects and appearance (3).
How to store onions?
Like shallots and garlic, onions should be stored in a cool, dry, and dark place away from heat sources like sunlight and stovetop. The pantry or kitchen cabinet works fine.
You can also store in the fridge to extend the onions’ shelf life as we mentioned above (1).
But before storing you should not wash the onions.. Washing food before keeping may stimulate bacterial development and accelerate decomposition, hence it is typically advised to wait until shortly before use to wash fruits and vegetables (4).
Do not keep the onions in a pile. The onions at the base of the pile may go bad quickly.
Keep the onions in a ventilated paper bag and leave it open. If you are using a bowl or container, do not cover it and let the onions breathe. Do not use a plastic bag for storing onions. It will block air circulation (2).
Keep the onions away from ethylene-producing fruits and vegetables like apples, bananas, and tomatoes (5).
Sliced, cut, or chopped onions should be kept in an air-tight container or freezer bag to seal the moisture and the pungent smell of onions (3).
Cooked onions should be placed in an air-tight container or freezer bag and stored in the fridge.
How to tell If an onion is bad?
To tell if onions are spoiled, you should be able to identify the possible signs of spoilage.
If the onions develop mushy spots that continue deep down the vegetable, discard it.
If the onion has black or brown moldy areas, it belongs in the bin. If the sliced or cut onions develop a slimy texture, they are spoiled. Bacteria growth on the outside such as Streptococci and Staphylococcus aureus can cause onions to get slimy (6).
If the onion gives off an off-odor, discard it. Spoiled onions can emit a strong, pungent odor similar to rotten eggs or sulfur. This smell is caused by the breakdown of sulfur compounds, such as allyl sulfide, which are naturally present in onions (6).
Normally onions have a light purple to a dark purple color but once they start going bad, their color changes from purple to a moldy green or brown which indicates that the vegetable is turning bad (7).
What is the shelf-life of onions?
If you have stored onions for longer periods, keep checking them now and then for spoilage. It is important to separate the moldy and spoiled onions to limit the spread of bacteria and fungus (7).
|In the pantry||In the fridge||In the freezer|
|Whole onions||1-6 months||2-3 months||Not recommended|
|Half-cut onions||Not recommended||18 days||Not recommended|
|Chopped or sliced onions||Not recommended||18 days||6-8 months|
|Cooked onions||Not recommended||3-5 days||Up to 3 months|
What affects the shelf life of onions?
Several factors affect the shelf life of onions. High humidity levels can promote mold growth and sprouting, leading to spoilage (8).
Exposure to excessive heat or temperatures above 4°C (40°F) can accelerate the onion’s natural decay processes.
Physical damage, such as cuts, bruises, or mechanical injury, can provide entry points for microbial growth and hasten spoilage. Onions that are harvested prematurely or are already damaged before storage have a shorter shelf life (8)
Additionally, storing onions near ethylene-producing fruits or vegetables can speed up their ripening and result in faster deterioration (5).
Proper storage conditions and careful handling are essential to preserve the quality and extend the shelf life of onions.
Does eating bad onions make you sick?
Consuming spoiled onions can result in foodborne illnesses and gastrointestinal problems. Spoiled onions may contain harmful microorganisms such as Salmonella, Escherichia coli, Listeria monocytogenes, and molds, which can cause infections and toxin-related illnesses (9).
These microorganisms can multiply on the surface or penetrate the layers of the onion, posing health risks upon ingestion.
Salmonella and E. coli can lead to symptoms like diarrhea, abdominal cramps, fever, and vomiting, while Listeria monocytogenes can cause severe illness, particularly in vulnerable individuals (9).
In this article, we answered the question “How long do onions last in the fridge?”. We also discuss how to store onions, what is the shelf life of onions, how to tell when they are bad and if bad onions can make you sick.
1. The Commercial Storage of Fruits, Vegetables, and Florist and NurseryStocks. Agricultural Research Service Agriculture, Handbook Number 66, 2016.
2. Sharma K, Lee YR. Effect of different storage temperature on chemical composition of onion (Allium cepa L.) and its enzymes [published correction appears in J Food Sci Technol. 2016 Mar;53(3):1633]. J Food Sci Technol. 2016;53(3):1620-1632.
3. Berno, N.D. Storage temperature and type of cut affect the biochemical and physiological characteristics of fresh-cut purple onions. Postharvest Biology and Technology, 2014, 93, 91-96.
4. Zander, A., Bunning, M. Guide to Washing Fresh Produce. Colorado State University, 2010.
5. Jin Gao, et al. Role of ethylene response factors (ERFs) in fruit ripening. Food Quality and Safety, 2020, 4, 15–20.
6. Ibemologi, A, Tolulope A. “Isolation and identification of bacteria from exposed and sliced Allium cepa (onions)“. Journal of Microbiology & Experimentation. 2022, 10, 224-227.
7. Can you use onions with black mold?. USDA, 2023
8. Gathambiri, C.W. et al. Postharvest losses of bulb onion (Allium cepa L.) in selected sub-counties of Kenya. African Journal of Food, Agriculture, Nutrition and Development. 2021, 21, 17529-17544.
9. What You Need to Know about Foodborne Illnesses. FDA, 2022.