Natural Flavoring

Question

When a product only has a small amount of something, it can be included in the designation "natural flavoring". This is so even if this very small amount also gives some flavor to the product. Since the "natural flavoring" can contain a non-kosher food, and indeed gives a taste -- which, after all, is why it is included in the first place -- then why isn't this forbidden under the rubric of taam ke-ikkar?