I don't support state enforced "truth in labelling", but if a company can lie to the state in order to put "cancer-free" on the label, it can also lie to the state in order to put banned carcinogens in the product.

I would support allowing companies to opt in to regulation (and pay the full cost of it) and only allow companies that have opted in to claim to be regulated by the relevant agency. That way, those who trust the state can choose to only use things the state has approved and no-one else will be harmed when the state is wrong.