Costco's popular private-label organic flour sold under the Kirkland Signature brand is manufactured and supplied by Central Milling, an employee-owned and operated agricultural company with deep operational roots spanning over a century. Established in Utah with historic milling facilities across the American West, Central Milling partners with major retailers to supply premium, USDA-certified organic, unbleached baking flours. By leveraging external partnerships with high-end millers like Central Milling, Costco ensures exceptional baking performance, consistent protein quality, and strict organic standards while passing significant cost savings directly down to wholesale members shopping in its massive warehouse locations.