The scientists measured levels of HMF in HFCS products from different manufacturers over a period of 35 days at different temperatures.

As temperatures rose, levels of HMF increased steadily. Levels jumped dramatically at about 120 degrees Fahrenheit (48.8 degrees Celsius), says a release of the American Chemical Society (ACS).

'The data are important for commercial beekeepers, for manufacturers of HFCS, and for purposes of food storage. Because HFCS is incorporated as a sweetener in many processed foods, the data from this study are important for human health as well,' the report states.

These findings appear in the current issue of ACS' bi-weekly Journal of Agricultural and Food Chemistry.