Which term describes the conversion of raw materials into food products, such as milling grain into flour?

The correct term that describes the conversion of raw materials into food products, such as milling grain into flour, is primary processing. This term refers specifically to the initial stages of transforming raw agricultural products into forms that are ready for consumption or further processing. In the case of milling grain, the raw grain is processed to create flour, which is a fundamental ingredient used in various food products.

Processing and manufacturing are broader terms that encompass various stages beyond initial transformation. Processing might include both primary and secondary stages, while manufacturing typically refers to the large-scale production of food products, often involving multiple steps and combining various ingredients. Production, although it generally refers to the creation of food items, does not specifically denote the initial transformation of raw materials, making primary processing the most accurate choice in this context.