A yearlong sting operation, including aliases, a 5 a.m. surprise inspection and surreptitious purchases from an Amish farm in Pennsylvania, culminated in the federal government announcing this week that it has gone to court to stop Rainbow Acres Farm from selling its contraband to willing customers in the Washington area. The product in question: unpasteurized milk. It’s a battle that’s been going on behind the scenes for years, with natural foods advocates arguing that raw milk, as it’s also known, is healthier than the pasteurized product, while the Food and Drug Administration says raw milk can carry harmful bacteria such as salmonella, E. coli and listeria.A sting operation. To stop whom? The Amish. From doing what? Selling milk.