Process manufacturing (used to make food products) is quite different from discrete manufacturing. In the most basic terms, process manufacturing creates stuff, and discrete produces ‘things’.
Process uses multiple recipes and variable ingredients which are blended and transformed into something new. Think honey, sugar, nuts, dried fruit, oats and coconut oil mixed together then baked to make a completely different product – a muesli bar. Each ingredient in the bar has a use-by-date, and its point of origin and batch must be traceable and accounted for. As must the final ready-to-eat bar.
Discrete takes standard parts and components and assembles them into widgets (well ok, that widget could be a million-dollar forklift). It’s an amalgam of components often with serial numbers fabricated into one larger ready-to-use product. The nature of the smaller parts isn’t changed by the manufacturing process.