Scientists engineered cordyceps (Cordyceps militaris) to safely produce supplements and edible biotech products without relying on antibiotic resistance genes. By deleting a gene required for uracil production (pyrG), they created food-safe fungal strains that can be genetically modified using nutrient markers instead, achieving up to 810 successful transformations per 100,000 spores. This breakthrough boosts the mushroom’s potential as a clean platform for future health ingredients.