You can leave sealed jars of pickled onions out but once opened the pickled onions must be kept refrigerated if not eating them within 2 hours.
Sealed jars of pickled onions can be left out but should be kept in a cool dark place such as a pantry or cabinet and opened jars of pickled onions must be kept refrigerated to prevent spoilage.
Leaving the opened jars of pickled onions out for a few hours is okay but any longer than that they can start to spoil.
Pickled onions that are kept sealed and unopened will last for around 2 years when stored in a cool and dark place.
Once you open the pickled onions they last for around 3 months.
After opening the pickled onions they should be kept refrigerated if not eating them within a few hours.
You can also freeze the pickled onions to make them last longer but the flavor and texture of the frozen pickled onions will change after a year of freezing.
When pickled onions have gone bad the brine will become cloudy.
The pickled onions when bad will also have an off or sour smell.
The pickled onions will also be mushy, discolored or slimy when bad.
And the jar may leak or spurt liquid or the lid will bulge.
Store the unopened pickled onions in a cool dark place such as a pantry or cabinet.
And keep the pickled onions away from heat or direct sunlight.
Always store opened jars of pickled onions in the refrigerator to prevent spoilage.