Process Contaminants: An Expert Perspective


What are “process contaminants” in food?  What are 3-MCPDs (3-monochloropropanediol) and GEs (glycidol/glycidyl esters)?  How did they get there, and what do they mean for the safety of our food?

These and other questions are discussed briefly in this educational podcast (and in a Q&A below) featuring Dr. Michael Dourson of the Risk Sciences Center at the University of Cincinnati College of Medicine.  Dr. Dourson, an expert in toxicology and environmental health risks, provides a general discussion and insights on what you should know about the process contaminants, 3-MCPDs and GEs that may be found in trace amounts in vegetable oils that are commonly used in many foods.

Q&A with Dr. Michael Dourson, Professor, Risk Science Center (formerly TERA), University of Cincinnati College of Medicine

What are GEs and 3-MCPDs?

These are naturally occurring, heat-formed contaminants that are typically detected is small amounts in vegetable oils. These oils, such as palm oil, are used for further processing in food. 3-MCPDs are not added to food. They are the product of the refining process for these oils, and the levels can also be affected by other natural elements such as harvesting conditions.

Which foods contain GEs and 3-MCPDs?

3-MCPDs were first identified in soy sauce. Since then they have been detected at low levels in a number of commonly eaten foods that are made with vegetable oils. Vegetable oils are today’s safe alternative to yesterday’s trans fat.

What’s being done to reduce GE and 3-MCPD levels in food?

Food companies have identified techniques to help reduce the amounts of these trace compounds in vegetable oils.  While technology exists to reduce them, it will take additional time for the entire industry, including vegetable oil manufacturers and companies, to update the equipment necessary to make these improvements.

What is the current health or dietary advice regarding GEs and 3-MCPDs in the diet?

The European Food Safety Authority (EFSA, 2016) determined that the mean exposure to 3-MCPD was above their estimation of a safe dose for infants, toddlers and other children.  However, the Joint FAO/WHO Expert Committee On Food Additives (JECFA, 2016) judged that the safe dose was higher than EFSA (2016) and that estimated dietary exposures to 3-MCPD for the general population, even for high consumers did not exceed their safe dose.  An independent analysis by the University of Cincinnati, College of Medicine supported the JECFA (2016) position.

For glycidol, both EFSA (2016) and JECFA (2016) found cancer changes in rats. Mean ratios of the levels at which these changes occurred to the much lower exposures in humans was a reassuring 11,300– 102,000.  However, infant exposures resulted in a mean ratio of 670 to 24,000.  These latter ratios may indicate some health concern, because both EFSA (2016) and JECFA consider ratios of 25,000 or higher to be of low health concern.

Based on what we currently know, should I be concerned about 3-MCPDs and GEs in food for me and my family?

No. Eating a variety of foods, and some that contain trace levels, will not harm us in any way. However, overeating any one food in particular, may lead to health risks not associated with 3-MCPDs or GEs. Everything in moderation is still a good lesson to live by.

Are you concerned about GEs and 3-MCPDs for yourself or your family?  Why or why not?

I am not concerned because the process of determining these safe or virtually safe doses is precautionary. It’s a margin of safety to protect you, me and our families. If exposures were to exceed the safe dose for 3-MCPD routinely, or if the margin of exposure was routinely less than 25,000 for GEs, health authorities, globally and including the FDA in the U.S., would provide the appropriate dietary recommendations to protect the health of the public. As of now, there is no need to change your diet.

Additional Resources:

Tony Flood of the IFIC Foundation contributed to this piece