Utilize the input text as a context reference, choose the right relationship between Dean Foods and milk from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

Aug 10 (Reuters) - Dean Foods Co's steeper-than-expected decline in quarterly sales and surprise departure of its chairman ahead of the earnings report sent shares of the largest U.S. milk processor down as much as 18 percent on Monday.

Answer: product_or_material_produced