H. W. Conn, The Story of Germ Life
“ Most of the bacteria that are left in the butter soon die, not finding there a favourable condition for growth; some of them, however, live and grow for some time and are prominent agents in the changes by which butter becomes rancid. The butter maker is concerned with the ripening rather than with later processes.The object of the ripening of cream is to render it in a better condition for butter making. The butter maker has learned by long- experience that ripened cream churns more rapidly than sweet cream, and that he obtains a larger yield of butter therefrom. ”
