The brand, which received approval to use soy leghemoglobin, aka heme, as a color additive from the Food and Drug Administration (FDA) earlier this year, launched its meatless patty in 27 Gelson's Markets in Southern California last week.
From tomorrow (September 26), the Impossible Burger will be available in grocery stores Fairway and Wegmans across seven states.
"More cities. More ways to make Impossible™ your own. Starting tomorrow, grocery shelves on the east coast will be stocked for you to #CookImpossible at home," Impossible Foods wrote on Instagram.
Impossible Foods itself consider its meatless patty to be plant-based rather than vegan.
This is because in 2017 a key ingredient - soy leghemoglobin (heme) - from the brand's flagship item the Impossible Burger was fed to rats in order to test its safety. An excess of 180 rats were killed as a result of the testing.
CEO Pat Brown reacted to the controversy, publishing a statement titled The Agonizing Dilemma of Animal Testing.