Before the mid-19th century, food and drink had an incredibly short shelf life, and in particular, milk deteriorated very quickly, becoming foul-smelling, undrinkable and wasted. This changed with the development of pasteurization, a process of heating liquid until almost boiling to destroy as many harmful microorganisms as possible before rapidly cooling it. Chemist Louis Pasteur made his discovery while researching the fermentation process of wine. He was attempting to discover the cause of sour or spoiled wine and that that rapid heating and cooling prevented any germs and microbes causing contamination.
