answer:Because they contain a lot of sugar. When you handle an ice cube, the surface of the ice melts with the contact of your skin, so there is a layer of liquid water against your finger. That water can’t be colder than 32F so the ice cube will always feel 32F. Sugar, like salt, lowers the freezing point of water (this is why salt gets mixed with the ice in old-fashioned ice-cream freezers). So when the liquid (syrup, really) of the banana melts against your skin, it can be considerably colder than 32F. That super-cold liquid pulls heat from your skin much faster than ice-melt does.