Every country has its own culture, traditions, and labelling regulations. Products that may not contain corn in Canada may be made with corn products in other places, even if the labels do not list corn products specifically. On the plus side, products that do typically contain corn in Canada may be safe in other countries. Staying safe requires the same in-depth knowledge of the regulation of ingredients on prepackaged food needed in Canada.
The safest bet is to eat foods prepared from scratch by friendly chefs.