Extrusion is a food processing technology method that incorporates numerous unit processes such as mixing, heating, kneading, shearing, shaping, and forming. The extruder is made up of a huge, revolving screw that is firmly fitted into a stationary barrel, at the end of which the die is located. As the screw turns, it pushes its way through the material inside the barrel, melting it and then pushing it out through the die like toothpaste from a tube. As you can see, this is an extremely efficient way to mix, heat, and form your ingredients into any number of shapes without having to stop the machine or adjust many different parts. The first extruders were developed more than 100 years ago and were used primarily for manufacturing plastic materials such as honeycomb panels, sheets, and bottles. Since then, advancements in computer technology have allowed for innovative designs that make other types of products possible using this same process. For example, an extruder can be used to create meat-and-cheese snacks that are shaped like worms or snakes and then cooked in their shells or coils on a line right before they are packaged for sale. Or an extruder can be used to create foam items such as furniture cushions or bedding products that use polyester fiber instead of feathers or cotton because these materials are easier to control with an extruder.