Impossible Foods, the Silicon Valley startup boasting “bloody” vegan burgers that have all the texture and flavor of meat, has encountered a setback due to its quest for greater transparency with regard to a key ingredient in the product. The startup sought an independent review of soy leghemoglobin from the FDA in 2014, but the agency has deemed that there is currently insufficient evidence of the ingredient’s safety for human consumption, according to documents obtained under a Freedom of Information request by the ETC Group.
“Although proteins are a part of the human food supply, not all proteins are safe,” reads the FDA response. “Information addressing the safe use of modified soy protein does not adequately address safe use of soybean leghemoglobin protein from the roots of the soybean plant in food.”
Soy leghemoglobin is used by Impossible Foods scientists to generate heme, the protein that gives meat its red color and slightly metallic flavor. Impossible Foods has performed extensive safety testing on soy leghemoglobin, and a panel of food safety experts from three different universities have confirmed the safety of the product, according to Business Insider.
While the FDA does not officially approve ingredients in food products, Impossible Foods elected to seek the Agency’s independent review.
“We respect the role the FDA plays in ensuring the safety of our food supply, and we believe the public wants and deserves transparency,” Rachel Konrad, a spokeswoman for Impossible Foods wrote in an email to the New York Times. She noted that the company was “voluntarily taking extra steps” to ensure that the burger was recognized as safe “because transparency is a core part of our company’s DNA.”
In an open letter published Thursday, Impossible Foods founder and CEO Pat Brown, a biochemist at Stanford University, refuted the findings of the Times article, saying that it was “chock full of factual errors and misrepresentations.”
“We wanted the FDA to review our GRAS determination, to have the added benefit of their expertise, and to assure consumers that our testing of leghemoglobin has passed the most rigorous scrutiny,” he wrote. “After submitting our GRAS determination, the FDA reviewed it, and had some questions.”
As it stands, the FDA has not deemed the protein unsafe, but rather has asked for further testing to prove its safety for human consumption. Impossible Foods can still sell its burger during this time, and the company plans to resubmit its petition to the agency with additional data this month.
“The Impossible Burger is safe,” Konrad said in a statement. “A key ingredient of the Impossible Burger — heme — is an ancient molecule found in every living organism.”
Impossible Foods was started in 2011 and has since raised $250 million in venture capital funding. The company secured a U.S. patent in July. It has wooed such chefs as David Chang of Momofuku with its promise to mimic the attributes and flavor of beef, as well as big-name investors like Bill Gates and Hong Kong billionaire Li Ka-Shing. In April, the company established a partnership with Umami Burger to sell the vegan burgers in nine Los Angeles locations.