It gets complicated. It is illegal for the company to use anything but real food to represent what they're selling--the milk people, for example, have to put real milk in those glasses, but cereal people can and do use glue instead. (Milk looks blue in the camera, apparently.) Further, they can't add more to the food--more lettuce, more tomato, more beef, or whatever--than they would actually put on it in the restaurant/frozen food box. Not so much as a sesame seed. However, they can use all kinds of tricks to make what they have look better. Often, they put cardboard rounds in burgers, for example, to lift them off the bun a bit.

For the curious, I read all this in a 1980-something issue of Penny Power, which was Consumer Reports for kids.

ETA: On further thought, clearly it's only food that can't be added, or somehow cardboard rounds don't count. Or I'm remembering wrong; Gods know it wouldn't be the first time.

__________________
Gillian

"Now everyone was giving her that kind of look UFOlogists get when they suddenly say, 'Hey, if you shade your eyes you can see it is just a flock of geese after all.'"

"You can't erase icing."

"I can't believe it doesn't work! I found it on the internet, man!"