A extremely generalisiere law like that is exactly what you would get out of a common law approach. If somebody sued somebody else about something the judge makes a judgment call about it, establishing a quasi standard. This quasi standard can then be revisited if needed.
The system that actually exists and many people here want is that every new product has to go threw a state facility that does testing and finds errors. Such a system actually exists and performs badly.
If a system of law is in action you can trust what you buy because you have trust that mass products are at least up to a minimum of standard. Sure, such a system probably does not find every detail. No system is perfect, a law based approach is generalized and low cost.
Here's a good start: If your product doesn't contain enough of X, you can't call yourself X.
That's why ice cream that is not real ice cream is called 'frozen dairy dessert' and cheese that's not cheese is a 'cheese product'.
I'm not for regulating all the products, but I'm also not going to carry a MRI scanner around and determine exactly what is what.