PRESENT STATUS OF PASTEURIZATION OF MILK. 7 
From a sanitary standpoint this process is very satisfactory. In the 
past, on account of the difficulty of treating large quantities of milk, 
pasteurization in bottles has not been used to any great extent in 
large plants. 
The bottling of hot pasteurized milk in steamed bottles is a process 
which eliminates the danger of reinfection and can easily be adapted 
to the treatment of milk in large quantities. 
Any one of these methods of pasteurization is satisfactory, pro- 
vided a temperature of 145° F. is maintained for 30 minutes and 
reinfection is prevented during subsequent handling of the milk. 
, SUPERVISION OF THE PROCESS OF PASTEURIZATION. 
As is the case with almost every known process which permits 
of variation by the operators, the process of pasteurization is fre- 
quently performed improperly. This is attributable sometimes to 
lack of care on the part of the operators, but probably more often to 
lack of proper knowledge of the functions of the process. Pasteuri- 
zation calls for supervision by competent inspectors to remedy such 
conditions, and supervision is provided for in only a few of the 
larger cities. In these cities the process must be performed by ma- 
chines approved by the boards of health, and at such temperatures 
and for such periods of holding as are required. 
In some cities pasteurized milk must be marked “ Pasteurized,” 
and in some cases the temperature must be stated, together with the 
date of pasteurization. 
In most of our cities there is a great lack of proper control over 
the process of pasteurization, and a standard method of pasteuriza- 
tion and definite procedure for proper supervision of the process is 
greatly needed. 
The process of pasteurization is by no means “ foolproof.” It 
demands a knowledge on the part of the operator of the action of 
the process and its objects. Not all operators have such knowledge. 
Records obtained in 1912 from 231 milk plants showed that 99 per 
cent of those which used the holder process pasteurized at the proper 
temperature. Among those which used the flash process only 57 
per cent employed temperatures high enough to give satisfactory 
results, while in the other 43 per cent the temperatures were too low 
to be effective in the destruction of pathogenic bacteria. At the 
present time this condition is much improved. 
Anyone who has had the opportunity to examine the numerous 
plants where pasteurization is practiced has undoubtedly found cases 
in which as many bacteria were introduced in cooling and bottling as 
“were destroyed by the heating process. It is in such cases that the 
operator’s ignorance of the fundamental principles of the process is 
