Don't worry about raw ground beef that's brown inside and red on the outside. The meat is naturally brownish, and turns red only when exposed to oxygen. When ground beef spoils it turns grayish throughout -- and usually smells "off" and feels slimy.
Choose a roast beef sandwich instead of a hamburger when dining out. Roast beef is traditionally much leaner than ground beef. Remember to watch the condiments. You'll negate the benefits earned from choosing the roast beef if you squeeze 3 ounces of mayo on the bun.