208 DOMESTIC ANIMALS, DAIRYING, ETC. 



Sterilized milk, properly speaking, is that which has had all 

 of its germ content destroyed. Hence if such milk be guarded from 

 further contamination, it will remain unaltered, even at ordinary 

 temperatures, for an indefinite period. To destroy all the germs in 

 milk, including the spores, it becomes necessary to subject it to the 

 action of live steam under pressure, at a temperature considerably 

 above the boiling point (240). Such a proceeding is neither prac- 

 ticable nor necessary in the household, as pasteurizing serves all 

 ordinary purposes. Milk may, however, be completely sterilized 

 by repeated pasteurization. The heating is repeated daily for nearly 

 a week, because all the spores present do not germinate after the close 

 of the first or even after the second heating, though there are very 

 few that remain. While milk sterilized by this method, has no 

 cooked flavor, yet it is a method commercially impracticable. 



What is generally called sterilized milk is not entirely free 

 from germs, but having been subjected to a more thorough heating 

 than with pasteurization, and being guarded against further con- 

 tamination, it will keep longer than does pasteurized milk. This 

 is its main advantage, for it has to a greater or less degree the cooked 

 flavor. 



The Simplest Method of Pasteurizing. If there is no objection 

 on the part of the consumer to the cooked flavor, the process of heat- 

 ing milk need not be so carefully done. No thermometer is needed. 

 All that is necessary is to bring the milk to the boiling condition. 

 But if one is to pasteurize milk it is necessary to use a thermometer. 

 One costing twenty-five cents is sufficient for this purpose. 



The simplest method of pasteurizing milk requires no addi- 

 tional apparatus aside from the commonest kitchen utensils. One 

 has simply to heat the milk as rapidly as possible in a common gran- 

 iteware pan, stirring all the while with a spoon of convenient size, 

 while the thermometer is held in the milk. As soon as the mercury 

 has run up to 185 (which occurs very quickly) the dish is covered, 

 removed from the fire and set aside. In our own practice we receive 

 the milk at 9 A. M. It is at once scalded at 185. This suffices for 

 the day. After supper, what is left, is heated again to preserve it 

 for breakfast. No refrigeration is used. Where the milk is received 

 in time for breakfast, unless some is needed through the night, the 

 second heating is unnecessary. In case there is no fear of disease 

 germs, what is used for the first meal or two (depending on the 

 season) can be used raw, while the portion that is reserved for later 

 use is heated. Milk can be kept for some days without ice, even in 

 warm weather, by this method of scalding night and morning. The 

 use of ice makes one heating a day to be sufficient. 



Pasteurizing Milk in Bottles. The bottles known as sterilizing 

 bottles are tall, narrow ones, with a capacity of eight ounces, or half 

 pint. After being filled with milk, the bottles are corked most con- 

 veniently by means of a wad or plug of cotton batting. But of course 

 care must be used that this does not become wet, and the bottles 

 must be kept upright. They may also be stoppered with ordinary 

 corks which have recently been boiled each time before using, and 



