How can you tell if an hard boil egg is bad?

Look for cracks or leaks in the shell. If the egg has been cracked, bacteria can enter and begin to grow, spoiling the egg.

Smell the egg. If the egg smells bad, it is likely spoiled.

Look at the color of the yolk. A fresh hard-boiled egg will have a yellow yolk. If the yolk is green or gray, the egg is likely spoiled.

Check the texture of the white. A fresh hard-boiled egg will have a firm white. If the white is runny or mushy, the egg is likely spoiled.

Trust your instincts. If you have any doubt about whether or not an egg is spoiled, it is best to err on the side of caution and discard it.