SPOTLIGHT: THE MILK MARKET
When you drink a glass of milk, there is a good chance it hasn't traveled more than a few hundred miles from the cow. Virtually every state has it's own dairy industry, with distinctively named brands of milk from Umpqua Dairy in Oregon to Golden Fleece Dairy in Florida. As a result, the market for fluid milk is mainly local.
in theory refrigerated milk could be safely shipped much farther than current distribution patterns. But a complicated set of government regulations -in place since the 1930s-discourages but does not prohibit long-distance shipments of fluid milk. In contrast, the market for dairy products such as cheese and butter is clearly global. The butter you put on a piece of bread may have come from as far away as New Zealand, and the cheese you eat may have come from France or even from Bulgaria, Lithuania, and Poland.