And in many places it's very difficult to find.
> Is that really a law? I have found food that there is no country or origin.<
I believe it is a law. But if a product is made in the USA, evidently you do not have to state that on the label. So in that case, the label would not have any country of origin information on it at all. Like you, I have seen that.
I find that odd. If you made your product in the USA, why wouldn’t you want to put that fact on your label?
https://www.cbp.gov/trade/rulings/informed-compliance-publications/marking-country-origin-us-imports