I can imagine that some foods have some inherent quantity of salt (e.g. seaweed), but I'm wondering of meat would have a significant of 'naturally-occurring' salt content. Specifically, I noticed some packages of ground beef that were labeled as containing some amount of salt; is it possible that none was added during packing, or any on the nutrition facts indicates added salt?
Tangential thought: how about olives? I've never tasted an unsalted olive, but I can't imagine that they grow 'salty' on the tree.