Of the 55 products they purchased from the local supermarket, the researchers found that one-third contained mercury, including products made by Quaker, Kraft and Nutri-Grain-all international and well-known brands.

The levels of mercury varied enormously, with the highest level being twice the amount of the lowest. The highest amounts were found in barbecue sauces, whereas the colas and soft drinks contained no mercury.

Nevertheless, Wallinga and the other IATP researchers strongly emphasize in their report - Not So Sweet: Missing Mercury and High Fructose Corn Syrup, published in January 2009 - that their findings are only a snapshot based on just a one-off purchase.

More important, they believe that the food and drink manufacturers are probably unaware that their products contain mercury, and they may not even be aware that mercury grade caustic soda is being used in the processing of the sweetener. And judging by the website of the UK's HFCS industry group, the IATP may have a point.

Indeed, on its website (www.highfructosecornsyrup.co.uk), the group reiterates that the FDA regards HFCS as a "natural product as the only two elements present in HFCS are fructose and glucose. Both fructose and glucose are naturally occurring sugars, and they also happen to be the sugars which form the disaccharide sucrose, which is commonly known as sugar". While this is true as far as it goes, the HFCS advocacy site fails to mention that the sweetener is derived from corn syrup, a glucose heavy product that would never contain fructose in its original form.

In other words, the "natural" claim is being used out of context: fructose is indeed natural, but not in association with corn syrup. In addition, there's no mention of the industrial processes involved in getting fructose into the product.

The Industry Response
American corn producers have been one of the chief beneficiaries of the explosion in HFCS usage, so it's not very surprising that its industry group, the Corn Refiners Association (CRA), was quick to refute Dufault's findings. It did not, however, respond to the IATP study and its discovery of mercury in a substantial number of snacks sweetened by HFCS.

CRA's president, Audrae Erickson, says the Dufault study is based on "outdated information of dubious significance". She claims that the industry has used mercury-free processing plants for several years - and yet, according to the IATP, four of the eight plants in the US still use mercury-based technology - and there may be many more plants around the world that are still reliant on mercury.

Erickson also reports that the FDA deemed HFCS safe in 1983 and again in 1996, although it was not made aware of Dufault's findings until 2005-since which time it has not issued any new statements on the safety of HFCS.

Erickson concludes by repeating the claim that HFCS is "natural" as it contains no artificial or synthetic ingredients or additives. However, it appears to be somewhat of a stretch to claim that any product is natural when it has passed through three industrial processes and used enzymes to create its final form. As Michael Jacobson, director of the Center for Science in the Public Interest, a US nutrition advocacy group, has said: "You're causing a change in the molecular structure and that shouldn't be considered natural." Instead, he believes that HFCS should be reclassified as an artificial sweetener.