Final answer:
Louis Pasteur's work indicated that bacteria could be agents of chemical change. He showed that microbial fermentation is caused by microorganisms and invented pasteurization.
Step-by-step explanation:
Louis Pasteur's work indicated that bacteria could be agents of chemical change. He conducted experiments on microbial fermentation and showed that it is caused by microorganisms. Pasteur also demonstrated that individual microbial strains have unique properties and invented pasteurization, which is a process used to kill microorganisms responsible for spoilage.