Migration of particles depends on the time of contact, surface area and solubility.Hardly any particles will migrate from the 3D printer into your product, with a teflon tube and stainless steel nozzle you will most likely be safe.As said before, use the same nozzle for all your food-grade parts and replace them regularly.If the filament is foodgraded, you can definitely sell products on your business' responsibility.Has anyone seen the FDA approval for HDGlass though? The datasheet has no information on that.