Check for soft or mushy spots on the onion. If the onion feels squishy or has areas that give under gentle pressure
Look for green shoots or sprouts emerging from the onion. While sprouting doesn’t necessarily mean the onion is bad
Examine the skin of the onion. If the outer layers are wrinkled, dry, or shriveled, the onion has been stored too long
Inspect for any unusual discoloration, such as dark spots, mold, or a change in color from the typical white, yellow, or red
Smell the onion. A strong, sour, or off odor indicates that the onion is no longer fresh. Fresh onions should have a mild, earthy smell.
Feel the onion’s texture. A healthy onion should be firm and crisp. If the onion feels slimy or wet, it’s a sign that it’s past its prime and may be starting to decompose.
Taste a small piece if you’re unsure. An onion that has gone bad may taste bitter or unusually harsh,
Check the root end of the onion. If you see extensive root growth or the roots are spreading, it’s a sign that the onion is no longer fresh and should be used soon.