Prairie Farms Dairy, Carlinville, Ill., added a lemon cream pie flavor last January. The yogurt contains 150 calories, 1.5 grams of fat and 5 grams of protein per 6-ounce container, with a suggested retail price of 59 cents. It joins the 13 other flavors in the company’s original low-fat line, including strawberry cheesecake, cherry vanilla and peach.