The controversy is growing over whether food should be labeled if it contains genetically modified organisms, known as GMOs. Currently, there is no mandatory labeling of GMOs in foods in Canada or most of the U.S. Yet, around 90 per cent of corn and soybeans produced in North America is genetically modified.

Consumer Reports tested a variety of foods to see just how widespread GMOs are and whether you can trust food labels. Since labeling is not required, you can’t tell by looking at the package, even though some may say “no GMO,” “Non GMO” or Non-GMO Project Verified.”

Testers analyzed more than 80 processed foods containing soy or corn to see if they contained GMOs. The food was bought between April and July of 2014 and at least two samples were tested from different lots.

Unless they were labeled organic, the vast majority of products without a specific claim regarding GMOs contained a substantial amount. Those included cereals, corn chips, snack bars and soy-based infant formulas.

A recent survey of 1,000 people found that more than 60 per cent believe “natural” means “no GMOs,” but that’s not what the tests have found. Virtually all the samples Consumer Reports tested that said “natural” but didn’t make claims about being organic or non GMO contained a high percentage of GMOs.

Products that were labeled with unverified claims, like “Non GMO” and “no GMO”, mostly proved accurate. The one exception was Xochitl original corn chips. They are labeled “no GMO” but contained a high proportion of GMO corn in all six samples tested. A spokesperson for Xochitl chips says its company and its supplier “are both baffled” by Consumer Reports’ test results. Xochitl’s “organic” white corn chips did meet standards for non-GMO.

Overall findings confirmed that the most reliable labels for avoiding GMOs are “Non-GMO Project Verified” or organic, both of which are independently certified.