As I understand it, the "truth in advertising" laws have really put a crimp in a lot of the really creative techniques in food photography. Apparently they don't like it if you need a bottle of glycerin to make every recipe actually look edible .
Many years ago I worked with a photographer who had shot 4x5 colour negatives of all of a chain restaurants standard menu items. Each time the restaurant expanded (and they did a lot of expanding then) the owners would order another set of colour corrected 8x10s of each item. They didn't use them for promotion - they used them in the kitchens as a visual reference to be used by the chefs and food preparation staff. That way, if a customer went to one of their restaurants and enjoyed a menu item, the customer could later go to another of the chain's outlets, order the same item, and receive a meal that was prepared and presented in a similar manner.