Place collards in a medium-sized pot. Fill pot with enough water to cover collards. Bring water and collards to a full-rolling boil. Lower heat to medium and cook for at least 20 minutes or until tender. Drain collards well and cool in the refrigerator. Place cooled collards in the refrigerator overnight. Chop the cold collards into small pieces. In a medium-sized bowl, combine the collards with sour cream, mayonnaise, vegetable mix, diced green onions, diced green pepper, parsley and Worcestershire sauce. Cover and chill to allow flavors to blend. Transfer to a serving bowl and serve with sliced vegetables.