WASHINGTON – The Food and Drug Administration (FDA) continues to assert that soy leghemoglobin (also known as “heme”) remains safe for use as a color additive in ground beef analogue products, which includes plant-based Impossible Burgers. The FDA on Dec. 17 said it concluded objections raised by the Center for Food Safety did not justify a hearing or provide a basis for revoking the safety assessment.

Impossible Foods Inc., Redwood City, California, in 2018 filed a color additive petition for the safe use of soy leghemoglobin as a color additive in ground beef analogue products such that the amount does not exceed 0.8 percent by weight of the uncooked product. The FDA in the Aug. 1 issue of the Federal Register published a final rule that added soy leghemoglobin to the list of color additives exempt from certification. The final rule may be found here.

Impossible Burgers are sold in more than 17,000 restaurants nationwide and are found in grocery stores, too, according to Impossible Foods. Burger King worked with the company to add the Impossible Whopper to its menus sytemwide.

The Center for Food Safety, a national non-profit public interest and environmental advocacy organization based in Washington, raised six objections to the final rule.

“After a thorough review of the objections submitted in response to the final rule, we have concluded that they do not provide any substantive evidence to cause us to change our determination of safety for the use of soy leghemoglobin as a color additive in ground beef analogue products,” said Dennis Keefe, Ph.D., the FDA’s director of the office of food additive safety, on Dec. 17.

The FDA responded to all six objections. The responses may be found here.

First, the FDA should have sought additional safety testing and public comment before approving the color additive for ground beef analogues that are not plant-based, according to the Center for Food Safety. The FDA responded that Impossible Foods addressed the safety of soy leghemoglobin, including any potential allergenicity, by using the weight-of-evidence approach, which is based on several elements such as the known function of the protein and its history of exposure, whether the protein is from a toxigenic or allergenic source, and the digestibility of the protein.

“Furthermore, we are not aware of any scientific evidence that suggests a food matrix, whether plant-based or animal-based, would modify the structure, function, or safety of soy leghemoglobin under the conditions of its intended use,” the FDA said.

Second, the Center for Food Safety said the FDA should require labeling the color as soy leghemoglobin/P[ichia] pastoris yeast protein, saying that such information would be vital for consumers who have allergies to soy products or yeast products. The FDA said foods that contain soy leghemoglobin must be labeled accordingly since soybeans are a major allergen. Yeast protein, however, has not been identified as a major allergen.

Third, the FDA should have required additional testing of the raw product. The FDA in response noted submitted safety studies were conducted using raw soy leghemoglobin preparations.

Fourth, the FDA independently should have verified the safety of soy leghemoglobin. The FDA said it disagreed that the FDA should conduct its own safety studies. Manufacturers or their paid contract laboratories mostly conduct studies that demonstrate the safety of food ingredients.

Fifth, the FDA should have required separate testing of P. pastoris since it is genetically engineered. The genetic engineering of P. pastoris produces soy leghemoglobin. The FDA responded that all the safety studies contained both the soy leghemoglobin protein and the P. pastoris proteins. Thus, no additional testing of a P. pastoris strain was needed.

Finally, the FDA violated the National Environmental Policy Act by failing to prepare an environmental assessment or environmental impact statement, according to the Center for Food Safety. The FDA responded that the Center for Food Safety provided no data or information to support the contention that approving soy leghemoglobin as a color additive would lead to an increase in the cultivation of genetically engineered soybeans, that such cultivation would result in an increase in pesticide use such as dicamba, or that cultivation would result in significant adverse impacts to threatened or endangered species or their habitat.