Combine the yogurt and cranberry juice in a blender. Add the strawberries and raspberries; blend until smooth
Strawberries: Remove the hull using the tip of a vegetable peeler or a sharp paring knife, Cut into quarters, place in a plastic bag and freeze until firm. Prep time for 1 pint: 6 to 8 minutes.
Raspberries: Sort through berries and discard any that are moldy or spoiled. Place in a plastic bag and freeze until firm. Prep time for 1 pint: 2 to 3 minutes. Yield: approximately 1 1/2 cups whole fruit.