According to the National Center for Home Preservation…
Properly canned food stored in a cool, dry place will retain optimum eating quality for at least 1 year. Canned food stored in a warm place near hot pipes, a range, a furnace, or in indirect sunlight may lose some of its eating quality in a few weeks or months, depending on the temperature. Dampness may corrode cans or metal lids and cause leakage so the food will spoil.
Here are some signs your home canned food has spoiled:
- The jar’s lid is not completely sealed.
- There are dried food streaks on the outside of the jar that originate from the top.
- There’s mold in the jar and/or on the inside of the lid.
- The contents smell off.
- The food has changed color.
- The brine or syrup in the jar is opaque or muddy.
- The contents are bubbly.
- The food spurts out of the jar when you open it.
The bottom line: