Idk about America but in my country laws were set for the farmers that all milk had to be sold to processing plants before being sold to consumers because the farms closest to the city were establishing a monopoly, thus evening out the market for dairy farmers, pasteurization was more of afterthought. In so doing a monopoly was ironically created since one company, owned by the farmers, controls the dairy industry. The libertarians hate it but it works very well.
It is difficult to set up a system were you keep small farms if you would just let the free market set the course.