Determining Country of Origin for Food Products: Guidelines?

For food and bath products, if the primary ingredient is imported to the US, then blended in the US, with a small percentage of a second US ingredient, is the Country of Origin the US or that of the primary ingredient?

Items are sold primarily within the US.

Imported by who? your vendor? 

Imported by us, direct from originating production facility.

US

You may need to list both, if it does not meet the vaguely promulgated "substantial transformation" criteria. I have not seen anything that outlines precisely what that term means.   If you mix two things and the pieces are recognizable, I would list both us and XYZ.  if the ingredients become a new product distinguishable from what is brought together, US.

  We are left, to a large extent, to our own judgement. 

From what I can tell, there is rarely a challenge to these claims and the primary reason it exists is to make sure import taxes are paid. the only entity that might enforce it is Customs and Border Protection.

The consumer being able to make an informed decision is also important, but it seems the market is much more tolerant of imported products than it was a decade ago.