How to judge whether the rice cake has gone bad?

There are three ways to see, touch and smell. 1 look; Look at the surface of the rice cake with your eyes for mildew or other color changes! 2 touch; Touch the surface of the rice cake with your hand to see if it is sticky! 3 smell; Smell the rice cake with your nose for rancid smell! Any of the above phenomena shows that the rice cake has gone bad!