Meat-free burgers made with an ingredient from genetically engineered yeast outsold ground beef burgers in US grocery stores where the two went head to head. In September, the plant-based, biotech-derived Impossible Burger began selling its uncooked product in stores for the first time. During the first two weeks, it became the overall top-selling patty fodder in many stores.

Made by Impossible Foods, the burger consists largely of soy protein, but looks, tastes and even bleeds like ground beef. Its key meaty flavor comes from heme, a molecule found abundantly in animal muscles, which Impossible scientists recreated using yeast. They fermented Pichia pastoris engineered with the gene for soy leghemoglobin, which contains heme (Nat. Biotechnol. 37, 573–480, 2019). The heme protein extract is separated and concentrated into a red liquid that, when added to soy protein and other ingredients, looks and cooks like raw ground beef. Impossible in July received FDA approval to use the red liquid as a color additive, which cleared the way for the alt-beef’s debut in retail stores (Nat. Biotechnol. 37, 110, 2019). The Impossible Burger in late September appeared on the West Coast in all 27 Gelson’s Markets locations, on the East Coast in all 100 Wegmans Food Market locations, and in two Fairway Market locations in New York City, according to Impossible Foods. In the first two weeks Gelson’s sold more Impossible Burger than all types of ground beef in both revenue and number of pounds sold, according to the company. More than 17,000 restaurants are already selling cooked Impossible Burgers, including Burger King and Qdoba in the United States and Beef & Liberty in Hong Kong.

Impossible is one of many groups engineering clever food ingredients. Researchers from the University of California, Berkeley on 30 September published a paper describing a way to engineer an oilseed plant to produce a human milk fat substitute for infant formula.