Milk preservation methods have improved starting with the arrival of refrigeration technology in the late 19th century, which included direct expansion refrigeration and the plate heat exchanger. These cooling methods allowed dairy farms to preserve milk by reducing spoiling due to bacterial growth and humidity.
Worldwide, leading dairy industries in many countries including India, the United States, China, and New Zealand serve as important producers, exporters, and importers of milk. Since the late 20th century, there has generally been an increase in total milk production worldwide, with around 827,884,000 tonnes of milk being produced in 2017
There has been substantial concern over the amount of waste output created by dairy industries, seen through manure disposal and air pollution caused by methane gas. The industry’s role in agricultural greenhouse gas emissions has also been noted to implicate environmental consequences. Various measures have been put in place in order to control the amount of phosphorus excreted by dairy livestock.