\"Golden Grains,\" a manufacturer of milled grain products, has identified metal contamination as a significant food safety hazard in their production process. Following a comprehensive hazard analysis based on ISO 22000:2018 principles and integrating HACCP methodologies, the team is determining the optimal Critical Control Point (CCP) for metal detection. The production line consists of the following stages: raw grain reception and storage, initial cleaning, grinding, sifting, packaging, and distribution. Considering the goal of preventing metal contamination from reaching consumers and adhering to food safety regulations, where should \"Golden Grains\" strategically place a metal detector to function as the most effective CCP? Assume that the initial cleaning stage removes most external metal contaminants, but the grinding process itself poses a risk of introducing metal fragments from the machinery. The effectiveness of each potential CCP location must consider the point at which metal contamination is most likely to occur and the ability to prevent further spread.