by Julie Fidler, Natural Society:
The FDA informed the manufacturer of Impossible Burger – a meat-like burger made using only plants – that it had not yet proven that the product’s key genetically modified (GM) ingredient is safe for consumption. The company, Impossible Foods, decided it knew better and launched the product anyway. 
The Impossible Burger is made using a GM form of a protein called soy leghemoglobin (SLH) or “heme,” which comes from the root nodules of soybean plants. An SLH gene is added to a yeast strain that is grown in vats using a fermentation process. Impossible Foods then isolates the heme from the yeast and adds it to the Impossible Burger, giving it a meat-like taste and blood-like red color.
Impossible Foods says on its website that it is “on a mission to make the global food system more sustainable.”
The company claims the Impossible Burger:
“…uses about 75% less water, generates about 87% fewer greenhouse gases and requires around 95% less land than conventional ground beef from cows. It’s produced without hormones, antibiotics, cholesterol or artificial flavors.”
The GMO faux-meat burgers are available at 43 restaurants nationwide, including several burger chains.
Documents obtained by ETC Group and Friends of the Earth U.S. through the Freedom of Information Act (FOIA) show Impossible Foods submitted an application to the FDA seeking GRAS (generally recognized as safe) status for SLH in 2014. The GRAS notification policy allows food manufacturers to decide for itself, independently of the FDA, whether or not a product is safe.
However, the FDA warned the company that SLH would not meet the basic GRAS status. The documents state:
“FDA believes that the arguments presented, individually and collectively do not establish the safety of SLH for consumption, nor do they point to a general recognition of safety.”