What these idealists forget is that while people used to live on more natural products, they were also pretty unhealthy. According to John A. Lucey, PhD, a professor of food science at the University of Wisconsin–Madison and director of the Wisconsin Center for Dairy Research, it’s estimated that in 1938, pre-pasteurisation, milk-borne outbreaks constituted 25% of all disease outbreaks (related to food and water) in the United States. Now, they make up fewer than 1%.