To keep sliced onions fresh in the fridge and prevent them from spoiling or developing an unpleasant odor, you can follow these simple steps:
Store in an airtight container: Place the sliced onions in an airtight container or resealable plastic bag. Removing as much air as possible will help slow down the oxidation process, which causes onions to spoil and develop a strong smell.
Use a moisture-absorbing packet: If you have a moisture-absorbing packet (like the ones found in some food packages or shoeboxes), you can add it to the container with the sliced onions. This will help reduce excess moisture and keep the onions fresher for longer.
Separate layers with parchment paper: If you have multiple layers of sliced onions, consider placing parchment paper between the layers. This will help prevent them from sticking together and make it easier to take out the desired amount without exposing the rest to air.
Keep them at the back of the fridge: The back of the fridge tends to be colder and more consistent in temperature than the front. Store the container of sliced onions in this area to maintain their freshness.
Avoid storing near strong-smelling foods: Onions can absorb odors from other strong-smelling foods, so it's best to store them away from items like garlic, cheese, or leftover fish.
Use them within a few days: While these storage methods can help extend the shelf life of sliced onions, it's still best to use them within a few days to ensure they remain fresh and flavorful.
Remember that even with proper storage, sliced onions will eventually start to lose their freshness. If you find that you have leftover sliced onions that you won't be able to use in a timely manner, you can consider freezing them. Place the sliced onions on a baking sheet in a single layer, freeze until solid, and then transfer them to an airtight container or freezer bag. Frozen onions can be used in cooking and will retain their flavor for several months in the freezer.