Today in 2001, US Patent 6326185 B1 was issued, an invention of Michael C. Barney, Kathleen M. Carrick, Alfonso Navarro, and David S. Ryder, assigned to Miller Brewing Company, for their “Method For Decontaminating Yeast.” Here’s the Abstract:

An improved method for reducing colony forming units bacteria in yeast is disclosed. The method involves contacting the yeast with a hop acid in an amount sufficient to give a final concentration of the hop acid of at least about 40 ppm.