Are Silk Products Cf/gluten-free? in Gluten-Free Foods, Products, Shopping & Medications Posted July 7, 2010 · Report to Admin I always thought that Silk Soy milk was free of gluten and casein, but I noticed that none of their products are on the listen of gluten/casein free products from Whole Foods. According to their website they are not certified gluten free, nor do they test for gluten. It used to have the label on it but no longer does. They do not ask their suppliers either. Some time next year they will have a form of testing in place, till then, who knows. I have noticed that it has been upsetting my stomach for the last few weeks so I switched to 8th continent. Problems gone. I have no idea about the casein, as that is not a problem for me.