Why do people use prop food?!
Answers: Why don't they just use real food?!
Real food tends to go bad quickly and the colors don't represent well on camera - that is why they use any number of fake ingredients when representing a "burger" or other food on TV.
You can re use and re use fake food, real food goes bad.
Even restaurant displays use prop food. Real food dries out, discolors, attracts insects, etc.
Real food doesn't stand up all day to photography & hot lights. It's interesting to watch food photographers. Pies are sprayed with urethane and the whipped cream you see is Shaving cream. When photographing roasts and stews, well the meat is seared for colour and then it gets sprayed with urethane and the same for meat in the stews and the vegetables are raw and just sprayed again to keep the lovely colours. The recipes are great but paper will not provide the lovely fragrance of cooking food or of the cooking smells in the kitchen and most people want to see what the finished product will look like. If all the photography could be completed within 15 to 30 minutes of the food being ready that would be great but it can't be as it takes hours for lighting, the best angles, even just photographing hamburgers, french fries or hotdogs.