Natural flavors

This comes the US Code of Federal Regulations (you can check out this, as well as the definition for artificial flavor in the Frontier Natural Product Co-Op Spice Glossary):

The term natural flavor or natural flavoring means the essential oil, oleoresin, essence or extractive, protein hydrolysate, distillate, or any product of roasting, heating or enzymolysis, which contains the flavoring constituents derived from a spice, fruit or fruit juice, vegetable or vegetable juice, edible yeast, herb, bark, bud, root, leaf or similar plant material, meat, seafood, poultry, eggs, dairy products, or fermentation products thereof, whose significant function in food is flavoring rather than nutritional.

And that...is clearly very vague.  I suppose maybe they keep it vague to protect any secret recipe or something, but it does seem a little crazy not to list where the flavoring is coming from (considering you could be eating a cracker that's flavored with chicken...and that could be a problem if you're a vegetarian).  Worse yet, I think if you have any kind of food allergy, you'd have to avoid anything that says "natural flavors" because there's no telling what it has in it.

I have a bottle of Nantucket Nectars juice on my desk, so for kicks, I just looked at the label.  Ingredients...filter water, sugar, pear and pineapple juice concentrates, guava puree, passionfruit and lemon juice concentrates, natural flavor, citric acid, ascorbic acid (vitamin c), vegetable juice and extract (for color), acacia gum.

Oh those natural flavors...they're even in juice (although I'm not sure why I thought it'd be more of a food thing).

I generally stay away from anything that has "natural flavor" in the ingredient list.  If it is a responsible company the ingredient will actually tell you in brackets what the natural flavor is ie: Natural Flavor (fruit extract) or (essential oil).

I made this decision when I found out a lot of companies hide MSG under the Natural Flavor label because MSG is technically a naturally derived ingredient.  The food industry and regulations surrounding it are so shady, it's sad really how deceiving it all is.