• Live life to the fullest with R.W. Knudsen Family Organic Just Tart Cherry Juice. This organic juice beverage is USDA-certified organic and Non-GMO Project verified. Full of antioxidants and no added sugar, add this 100% juice is perfect to add to smoothies, cocktails and mocktails. Plus, each eight-fluid-ounce serving of this fruit drink provides a one-cup serving of fruit.