This can be a good thing. It's the reason that ice cream isn't as hard as a rock. It's because there's always a liquid phase. But when it comes to fruits and vegetables, there's a problem, because these foods contain chemical agents called enzymes.ENZYME: [sock puppet appears].Now enzymes set various natural changes into action, such as decomposition and ripening. And unlike bacteria, enzymes are impervious to the cold.E: [disappears and reemerges wearing a coat]AB: Oh. Hey, nice coat.