Earlier quoted context omitted.
I understand there are specific laws about what they can and cannot show in a food ad in Ontario and/or Canada. They can do their own preparation, but I believe the ingredients must be identical to the ones in the actual product. So it must be an actual beef patty, and the ketchup and mustard can be squirted on carefully, but they have to be real ketchup and mustard.
A well-known food celebrity in Jamaica told me once that most ice-cream ads actually use mashed potatoes. I didn't know enough to ask her if that was a local or international practice.
But there is a difference between just food in a photo-shoot where you can use anything and a shot of the actual product in an ad which must obey certain rules in most countries