Preheat oven to 350 degrees F.
In a small bowl, mix together the horseradish, mustard, salt, and pepper. Set aside.
In large bowl, mix ground beef, onion, egg, and Worcestershire sauce. Add contents of small bowl and mix thoroughly. Add the bread crumbs and combine well.
Place mixture into a 1-pound loaf pan. Pour ketchup over top and place in oven.
Bake uncovered for 45 to 60 minutes.
Professional Recipe: This recipe was provided by a chef, restaurant or culinary professional and makes a large quantity. The Food Network Kitchens chefs have not tested this recipe in the proportions indicated and therefore cannot make any representation as to the results.