The diagrams below give information about the manufacture of frozen fish pies.

The pictures illustrate the ingredients that go into a factory-made fish pie, and the various steps in its production. The pie contains salmon, peas, sauce and potatoes, and there are ten stages in its manufacture, from delivery to dispatch. One of the ingredients, potato, goes through its own six-stage preparation process before it can be added to the pie. Potatoes are the first ingredient to be prepared on the production line. They are delivered to the factory up to a month before the process begins, and they must be cleaned, peeled and sliced. Potato peelings are thrown away, and the sliced potatoes are boiled, then chilled and stored. When fresh salmon arrives at the factory, lemon juice and salt are added, and the fish is cooked in a steam oven within 12 hours of delivery. Next, factory workers remove and dispose of the skin and bones, and the fish is inspected. Following inspection, pre-prepared peas, sauce and potatoes are added. The resulting fish pies are wrapped, frozen and then stored or dispatched.