STERILIZATION OF MILK. 159 



To accomplish this sterilization effectually various ma- 

 chines have been invented and patented. Although different 

 in construction, they are all based upon essentially the same 

 principle. Milk is placed in bottles and subjected to a steam 

 pressure of a certain definite amount, for a proper length of 

 time, and then -the bottles hermetically closed without being 

 exposed to the air. The milk in these closed bottles is then 

 kept indefinitely, the assumption being that the sterilization 

 is so complete that it removes all possibility of subsequent 

 bacterial growth in the milk. Bottles are kept sealed until 

 used. 



Such a method of furnishing a sterile milk was adopted 

 several years ago and, for a time, promised to be widely 

 adopted. In European cities such sterilized milk has been 

 on sale for some years. The process, however, has never 

 been very popular anywhere, has hardly been tried in Amer- 

 ica and, at present, seems likely to be abandoned, at least 

 for ordinary purposes. It is safe to say that such a method 

 will not likely be adopted for the general milk supply. There 

 are objections against such milk more than sufficient to 

 counterbalance the value of having milk free from bacteria. 

 These objections suggest so much information concerning 

 our general subject that they will be briefly considered. 

 They are chiefly as follows : 



1. The expense of such a process is considerable and the 

 milk must be sold at a price higher than that of ordinary 

 milk. This might not be sufficient to prevent its use among 

 wealthy families, but the poorer people could hardly adopt it. 



2. The taste of the milk is altered, the cooking which the 

 milk thus receives imparting to it the well-known taste of 

 boiled milk. The intensity of this boiled taste varies with the 

 different methods. Some samples of sterilized milk show 

 this new taste very slightly, while others show it very 

 strongly ; but it is always noticeable. Now it may be that 

 the public might learn to enjoy such cooked milk, and it is 



