A lot of folks in child comments are echoing your sentiment that something “cannot be proved safe”. Your argument that proving something is “not unsafe” is proving a negative is fallacious; the same can literally be said about anything (proving something is X is the same as proving it is not not-X). Proving drugs are safe and effective is literally one of the jobs of the FDA. If you do not believe that is possible, then we may as well tear down the entire drug regulatory apparatus. I imagine you and many other commenters will sing a different tune when posed with that suggestion.

So, let’s stop pretending it’s not possible. We require drug companies show their products are safe and efficacious, and there is both a scientific and a legal framework by which we do this. Let’s debate whether or not the same framework should be applied to food additives (I would argue it should) rather than claim it is not possible.