Dr. Stopford, a graduate of Harvard Medical School, is an internist and occupational physician at Duke University Medical Center in the Department of Community and Family Medicine, Division of Occupational and Environmental Medicine where he directs a toxicology program. He has 36 years of experience as a practicing physician. He is widely published and has taught numerous courses and seminars on toxicology, occupational health, and family medicine. Dr Stopford is a renowned expert on the health effects of mercury, and has conducted extensive research on the subject.
•)No quantifiable mercury was detected in any of the samples analyzed.
•)High fructose corn syrup does not appear to be a measureable contributor to mercury in foods.
I have reviewed the results of total mercury testing of samples of high fructose corn syrup conducted by Eurofins Central Analytical Laboratory (Metairie, LA) in February and March 2009. One hundred nineteen samples of high fructose corn syrup (HFCS 42 and HFCS 55) supplied by the 5 U.S. and Canadian producers from each of their 22 production facilities were analyzed.
Samples were collected after decontaminating surfaces to prevent unexpected mercury contamination of samples. Samples were digested in nitric acid and hydrogen peroxide in high pressure Teflon vessels using microwave heating in conformance with AOAC Official Method 986.15, developed for digestion and analysis of human and pet foods for heavy metals. Digestion samples were then analyzed for mercury using EPA Method 200.8, an analytical method utilizing inductively coupled plasma-mass spectroscopy (ICP-MS) which is specified by EPA for analysis of drinking water. Samples of high fructose corn syrup were spiked with mercury to act as positive controls with acceptable results if mercury recovery was in the range of 70-110%. For every 10 samples analyzed, a reference sample with a known level of mercury was also analyzed. Samples were analyzed in duplicate. I reviewed and approved these methods prior to the initiation of testing.
No quantifiable mercury was detected in any of the samples analyzed under the parameters of the method with a limit of quantification of 0.005 mg/kg or 5 parts per billion (ppb) and a detection limit of 2 ppb. Detection limits for mercury analysis by ICP-MS range from 0.4-3 ppb depending on the product type being sampled (Ysart et al., 2000).
Mercury in various food groups can range up to 141 ppb with levels generally <18 ppb in the last 10 years (Stopford, 2009). High fructose corn syrup with <5 ppb mercury would not be a significant additional contributor to mercury in foods.
Stopford W, Normal mercury levels in food and beverages. 2009. http://duketox.mc.duke.edu/recenttoxissues.htm
Ysart G, Miller P, Croasdale M, Crews H, Robb P, Baxter M, de L’Argy C, Harrison N.
1997 UK. Total Diet Study-dietary exposures to aluminium, arsenic, cadmium, chromium, copper, lead, mercury, nickel, selenium, tin and zinc. Food Food Addit Contam. 2000 17(9)775-786.)))))))