Final answer:
The medical center's practice of chilling menu items until they are heated for serving is known as a ready-prepared foodservice operation.
Step-by-step explanation:
The type of foodservice operation where a medical center produces and chills menu items until they are heated for serving is known as a ready-prepared foodservice operation. This method is distinct from a conventional operation, where meals are made to order, a commissary operation, where food is prepared at a central location and then shipped to various locations for final preparation and serving, and an assembly/serve operation, where fully prepared foods are purchased, stored, assembled, heated, and served.