It is a well-known fact that all butter deteriorates in quality after its manufacture, and that if the fresh, sweet and clean flavor of butter could be retained for a longer time, the butter would command a much higher price on the home as well as on foreign markets, and more of it would be consumed. It is also evident that some factories can manufacture butter with better keeping qualities than others, and consequently receive more pay for their product. This, in itself, would indicate that it is through the different steps of manufacture that precautions are to be taken in order to secure the best keeping qualities in butter.
M'Kay, G. L. and Larsen, C.
"The keeping quality of butter.,"
Bulletin: Vol. 7
, Article 1.
Available at: https://lib.dr.iastate.edu/bulletin/vol7/iss71/1