French biologists observed that cultures of the anthrax bacilli when contaminated with molds could be successfully inhibited

By this time, Bacillus anthracis had been shown to cause anthrax, the first demonstration that a specific bacterium caused a specific disease. In 1877, French biologists Louis Pasteur and Jules Francois Joubert observed that cultures of the anthrax bacilli, when contaminated with molds, could be successfully inhibited. Some references say that Pasteur identified the strain as Penicillium notatum.