When Alexander Fleming famously discovered penicillin in 1928, he stumbled upon a medical miracle. However, his strain, Penicillium notatum, produced antibiotic compound in frustratingly tiny trickles. By the onset of World War II, scientists knew penicillin could cure battlefield infections, but they lacked a way to brew it in industrial quantities.
Enter the Northern Regional Research Laboratory in Peoria, Illinois, where researchers spent years hunting for a super-strain of mold. They hired a local woman named Mary Hunt—affectionately dubbed 'Moldy Mary'—to scour local markets, fruit stands, and bakeries for any moldy food samples she could find. In the summer of 1943, Mary brought back a grocery store cantaloupe covered in a golden, velvety mold.
Laboratory tests revealed that this strain, Penicillium chrysogenum, produced 200 times more penicillin than Fleming's original mold. When scientists exposed the Peoria melon strain to X-rays and ultraviolet light, they created mutants that yielded over 1,000 times the original output. Deep-tank fermentation techniques were rapidly adapted to feed this mold on corn steep liquor, an agricultural byproduct abundant in the Midwest.
Within months, American pharmaceutical companies scaled up production, producing billions of units just in time for D-Day in 1944. Ultimately, a spoiled melon transformed an impossible laboratory rarity into the world's first mass-produced wonder drug.