The process industries are those industries where the primary production processes are either continuous, or occur on a batch of materials that is indistinguishable. For example, a food processing company making sauce may make the sauce in a continuous, uninterrupted flow from receipt of ingredients through packaging. Or batches may be produced depending on the cook kettle sizes but immediately combined and re-routed. In either case, there is no concept of a unit of sauce while it is being processed. Examples of the process industries include food, beverages, chemicals, pharmaceuticals, petroleum, ceramics, base metals, coal, plastics, rubber, textiles, tobacco, wood and wood products, paper and paper products, etc.