Impossible Foods will sell its plant-based burger in grocery stores in September after the Food and Drug Administration approved its key color ingredient.

The FDA said it has cleared Impossible Foods' use of soy leghemoglobin — or heme — as a color additive, clearing the way for the maker of imitation meat to start selling its products in grocery stores.

Impossible Foods genetically engineers yeast to create heme, the iron-containing molecule that gives meat its taste and aroma.

The New York Times reported in 2017 that the FDA was concerned about the safety of heme, given that it had never been consumed by humans. Last year, the FDA deemed soy leghemoglobin “generally recognized as safe.” But in order to sell its uncooked vegan burgers in grocery stores, Impossible needed the FDA’s approval to use the ingredient as a color additive.

“We’ve been engaging with the FDA for half a decade to ensure that we are completely compliant with all food-safety regulations — for the Impossible Burger and for future products and sales channels,” said Dana Wagner, Impossible Foods chief legal officer in a statement.

For now, Impossible Foods has been able to distribute its product only by selling it in restaurants. After starting with high-end restaurants, Impossible’s plant-based burger has made its way into fast-food chains like Burger King and White Castle.

If the FDA does not receive any objections from anyone adversely affected by the ingredient in 30 days, Impossible Foods can start selling the product directly to consumers.