Scientists discovered a beneficial bacteria called Bacillus velezensis HX0039 that can protect ‘Sanghuang’ mushrooms from harmful green mold disease. This bacteria produces natural antifungal compounds like iturin A that stop the disease without harming the mushrooms or the environment. Testing showed it was 83% effective at preventing green mold and was completely safe for both mushroom cultivation and animal consumption, making it a promising alternative to chemical fungicides.