However, melting is often the desired effect - a hand covered in melting ice cream looks cool and every body loves a great drip shot. Some times you have to fake it a little bit. I've seen food stylist use hair dryers to melt ice cream faster or they'll even do the drips themselves!
While the end result is usually a fun and playful image, the reality of shooting such things is pretty messy and quite challenging. There is a lot involved in such a shoot: you are either dealing with something that is melting too fast or too slow, timing is always an issue for the perfect drip shot, and holding something frozen can really start to hurt after a few minutes.
The final images are always exciting at least!