~Culture vs. home-made starters.~ One great advantage which has accrued from the use of culture or commercial starters has been that in emphasizing the need of closer control of the ripening process, greater attention has been paid to the carrying out of the details. In the hands of the better operators, the differences in flavor of butter made with a culture or a natural starter are not marked,[168] but in the hands of those who fail to make a good product under ordinary conditions, an improvement is often secured where a commercial culture is used. ~Pasteurization as applied to butter-making.~ This process, as applied to butter making, is often confounded with the treatment of milk and cream for direct consumption. It is unfortunate that the same term is used in connection with the two methods, for they have but little in common except in the use of heat to destroy the germ life of the milk. In pasteurizing cream for butter-making, it is not necessary to observe the stringent precautions that are to be noted in the preservation of milk; for the addition of a rapidly developing starter controls at once the fermentative changes that subsequently occur. Then again, the physical requirement as to the production of a cooked taste is not so stringent in butter-making. While a cooked taste is imparted to milk or even cream at about 158 deg. F., it is possible to make butter that shows no permanent cooked taste from cream that has been raised as high as 185 deg. or even 195 deg. F. This is due to the fact that the fat does not readily take up those substances that give to scalded milk its peculiar flavor. Unless care is taken in the manipulation of the heated cream, the grain or body of the butter may be injured. This tendency can be overcome if the ripened cream is chilled to 48 deg. F. for about two hours before churning. It is also essential that the heated cream should be quickly and thoroughly chilled after being pasteurized. The Danes, who were the first to employ pasteurization in butter-making, used, in the beginning, a temperature ranging from 158 deg. to 167 deg. F., but owing to the prevalence of such diseases as tuberculosis and foot-and-mouth disease, it became necessary to treat all of the skim milk that was returned from the creameries. For this purpose the skim milk is heated to a temperature of 176 deg. F., it having been more recently determined that this degree of heat is sufficient to destroy the seeds of disease. With the use of this higher temperature the capacity of the pasteurizing apparatus is considerably reduced, but the higher temperature is rendered necessary by the prevailing conditions as to disease.