Is color additive that makes Impossible Burgers "bleed" safe?

A genetically engineered color additive that makes Impossible Foods' plant-based burgers appear to "bleed" like real meat should not have been approved by the Food and Drug Administration without more extensive testing, a food advocacy group says.

The Center for Food Safety is challenging the FDA's 2019 approval of soy leghemoglobin, a so-called heme colorant produced in genetically engineered yeast that is used in the vegan burgers now sold in supermarkets and restaurants across the country, according to a court documents filed last week. 

"Because [genetically engineered] heme is new to the human diet, and substantial quantities are added to the Impossible Burger, FDA should have required extensive safety testing before approving its use as a color additive, as required by law," the nonprofit group said in a statement. 

According to Bill Freese, the center's science policy analyst, the federal agency gave the substance the green light without long-term animal studies looking at potential adverse effects including cancer and reproductive impairment. 

"We find this to be all the more troubling because a number of potential adverse effects were detected in a short-term rat trial: disruption of reproductive cycles and reduced uterine weights in females, and biomarkers of anemia, reduced clotting ability, and kidney problems," Freese said.

Reached for comment, an FDA spokesperson said by email that the agency does not comment on possible, pending or ongoing litigation. 

Impossible Foods dismissed the notion that its products might be unsafe to consume, with a spokesperson saying in an email that all had "undergone rigorous safety testing and meet or exceed all relevant federal requirements."

The company also accused the Center for Food Safety of having an axe to grind against Impossible Foods, calling the non-profit focused on improving food production an "anti-GMO, anti-science organization." 

Impossible Foods has seen explosive growth, with the plant-based protein maker's products sold worldwide. The California-based company recently introduced soy-based products mimicking pork and sausage, and its burgers are sold at major restaurant chains including Burger King. 

While questioning what it terms the "premature introduction" of Impossible Foods products containing genetically engineered heme in supermarkets and restaurants across the country, the Center for Food Science said it "avidly supports plant-based eating." 

Impossible Burger has said its vegan products are environmentally friendly as they use less land and water and produce fewer greenhouse gases than animal products do. But some health experts are skeptical of processed alternative burger products' nutritional values, saying they come with a fair helping of saturated fat, for instance.