Commercial high fructose corn syrup as well as foods containing the ingredient may possess a dangerous component - mercury. About 1 in 3 food items tested in recent studies had mercury above the detection limit, and researchers believe that mercury-grade caustic soda used in the corn syrup manufacturing process is to blame. Food processors and members of the corn syrup industry say the findings are outdated and flawed - the studies were based on samples taken in 2005 - and the president of the Corn Refiners Association maintains that the industry has used mercury-free versions of the reagents for several years.