Aramark is primarily a logistics company. If you ask them to deliver x number of pieces of dry aged 8 oz sirloin of the finest quality, several containers of different spices, and the finest fresh potatoes and vegitables, that is what they will do, and how you prepare it is your business.
If you ask them to send you x number of pieces of pre-marinated unspecified steak, a packed steamable bag of unspecified vegetable medley, and a pack of premmade or instant mashed potatoes, they will do that, too, and the amount of preparation the chef is responsible for is limited.
If, as many corporate facilities do, you ask them to supply an entire cafeteria menu and the employees to staff and run it, for a guaranteed income or profit, they do that, to the specifications of the contract. My experience during a time in my life where I was day vendoring at corporate cafeterias is that the food varied a lot more campus to campus than whether it was Aramark, Sodexo, internal to the company, or a renting vendor trying to run a small business.