Natalya Murakhver, a New York food writer and mother of an 18-month year old daughter, loved her premium brand orange juice -- the "100 percent pure" and "not from concentrate" kind that comes in the colorful carton and tastes consistently delicious. That is, until she said she learned from her first-time moms group that there's a "secret ingredient" in all premium orange juices that companies are not required to put on their labeling. Now, after writing Whole Foods, she refuses to buy her favorite, "365" juice, amid uncertainty about its contents. "One of the moms said she had read about...