Is mustard the only food that doesn't spoil?

Answer 1

Prepared mustard might not spoil, but it can lose flavor and change color. And becomes watery .

Honey is one food that does not spoil.

Honey will turn to hard sugar (inedible) eventually.

Answer 2

Foods irradiated with ionizing radiation such as gamma rays, electron beams and X-rays can be stored almost indefinitely as long as their packaging is unopened.

Additional information:

Honey can be kept indefinitely, additionally. Many dried and packaged foods can be kept indefinitely. Canned foods will not spoil if they are not opened. Grains that are stored properly, sugars and candies, unopened bottles of wine and beer, properly sealed jars of fruit jams, jellies and preserves - as long as they are kept cool and dry and the seals of the packaging are not broken, will all keep indefinitely.