I hear often, especially in regards to our Corn-Free List, that the company says it's corn-free so it's corn-free.
Corn-free means a lot of different things to different people. If you ask an every day normal by-stander if their hamburger is corn-free, they'll tell you yes. They're looking for corn kernels, and since there are none it is corn-free. A few might say that they don't know thinking there may be corn syrup or corn starch in the bun or condiments.
This is not sufficiently corn-free for the corn allergic.
A letter posted on a Delphi-Member's site from the University of Nebraska - The Food Allergy Research & Resource Program, which is often asked to test foods for proteins so companies can make "-free" claims, had this to say about corn-free claims in the USA:
"...in the U.S., there is no regulatory definition for terms such as corn-free on product labels. Thus, companies can establish their own definitions and there can be considerable variability. Obviously that is not a desirable situation as such terms can sometimes be quite misleading."
This is very truly the case with corn-free labels on packaging as it's been tested by corn allergic human subjects, sometimes successfully and sometimes disastrously. It's hit and miss, which is why we require human-testing for any product that we suspect to be corny or that would be high risk. As much as we'd love to, we cannot just take a company's word for corn-free status.
This doesn't mean you shouldn't contact companies though. As companies can confirm for you that something definitely is corn, which can save you from trying it out. It simply means that even though a company has said "Yes this is corn-free" you should still use caution until you've tested it yourself.
As I've posted once before, we don't believe that companies are using false corn-free claims in order to do harm, but merely that they lack understanding of what constitutes corn-free and/or that their suppliers are not well informed.
University of Nebraska - The Food Allergy Research & Resource Program "does not have an analytical method to test for corn so we would certainly not have performed any testing for corn." So if you see FARRP mentioned as the source for their corn-free claim, please notify the FARRP organization at UNL (here).
Please also keep in mind that tests for "-free" claims do allow a certain amount of proteins to be present (parts per million - ppm) so if it's made from corn, and claimed that the corn is processed out of it, there still could be a protein left (your allergy may not even be protein based, but that's another story).