This list is far from comprehensive.
Note that “condiments” includes, but is not limited to, jams, chutneys, mustard, wasabi, flavoured honey (but not pure honey), sauces, dips, spreads, peanut butter (!), spice mixes/powders, pickled vegetables and candied fruit. Generally speaking, if a product is “low fat,” the fat that would have been in the original version is replaced with a corn-based thickener.
For information on xanthan gum and on flavour preparations, see below the chart.
Also please note that, while most American web sites about corn allergy list vinegar as a product corn-sensitive people should avoid, in Canada only malt vinegar may contain corn. Other types of vinegar are not made with corn products. (The document linked to here is section B.19.005 of Canada's Food and Drug Regulations. Sections B.19.001-B.19.009 deal with vinegar).
|Corn derivative||Use||Examples of foods likely to contain it|
|dextrose||thickener, sweetener||cold cuts, cream, ice cream, yogurt, canned soup, processed cheese, artificial sweetener, products for diabetics, nuts|
|dextrin||thickener||cold cuts, pastries, condiments, canned soup|
|maltodextrin||thickener||cold cuts, pastries, condiments, canned soup, artificial sweetener, products for diabetics|
|corn syrup||sweetener||cold cuts, sweet drinks, candy, condiments, nuts, including some brands of chestnuts in the shell!|
|glucose||sweetener||sweet drinks, candy, pastries, condiments|
|glucose-fructose||sweetener||sweet drinks, candy, pastries, condiments, processed cheese|
|fructose||sweetener||sweet drinks, candy, pastries, condiments|
|invert sugar||sweetener||pop and other sweet drinks, candy, pastries, condiments|
|corn starch||thickener||cold cuts, pastries, ice cream, yoghurt, custards/puddings, condiments, preseasoned meat|
|modified starch||thickener||same as for corn starch|
|starch||thickener||cold cuts, pastries, ice cream, yoghurt|
|corn oil||oil||anything baked or fried, condiments, nuts, raisins|
|vegetable oil||oil||anything baked or fried, condiments, nuts, raisins|
|margarine||oil||anything baked or fried|
|shortening||oil||anything baked or fried|
Notice that many of the names of these corn derivatives do not involve the word “corn.” Even corn syrup sold in Canada does not have “corn” in its ingredient list!
In fact, some of the sweeteners, thickeners, etc. in the list above can also be made from plants other than corn – but because the labeling laws in Canada do not compel food retailers to indicate when this is the case, it's better to be safe by avoiding those products that may be made from corn.
Also keep in mind that these products contain varying amounts of allergenic materials, depending on how they were manufactured. It is possible to react more strongly to some of them than to others. Of course, it also depends on how much of these products are in the foods in the first place.
For instance, the overall amount of corn residue is probably extremely small in xanthan gum and in proprietary flavouring preparations. I personally don't react to either of these things.
Xanthan gum is a goopy substance made when the helpful bacterium Xanthomonas campestris links sugar molecules together into a branching chain (polysaccharide). It is used as a stabilizer and thickener in foods and drinks. The Xanthomonas bacteria are usually but not always fed corn syrup (scroll down to “Description”), but they can also be grown on other sources of sugars, including beer, milk products, peach pulp, and cassava.
Proprietary flavour preparations are often stabilized with dextrose, dextrin, or maltodextrin, but they constitute such a small percentage of the weight of the final food/drink that manufacturers are not compelled to list their ingredients on the packages (see links here). It is possible to find out whether these preparations contain corn derivatives by calling the companies and asking.
Here is a PDF brochure from Casco, an Ontario corn processing company, with a detailed list of products made from corn and sold in Canada.
Here is an industry web site explaining how corn starch and corn oil are made. If you know some chemistry and have access to relatively old journals, you can find more information about the history of the development of corn syrup as a commercial product in this article: James P. Casey, “High fructose corn syrup – a case history of innovation.” Research Management. September 1976. 19 (5): 27-32, also published in Cereal Foods World, 1977, 22: 48-55, 76, and in Starch/Stärke, 1977, 29 (6): 196 - 204 ( available here, for a fee).