PRESENT STATUS OF THE PASTEURIZATION OF MILK 6 
temperatures are used chemical changes do occur. He also brought 
out the fact that 5 per cent of the albumin is rendered insoluble by 
heating the milk for 30 minutes at 150°, whereas 30.78 per cent of the 
albumin is coagulated at 160°. Further evidence that low-temperature 
pasteurization does not injure the digestibility and nutritive value of 
milk has been brought out in feeding experiments with babies. In 
experiments conducted by Weld (61) a number of babies were fed 
raw milk and pasteurized milk, and there was only a slight difference 
in the average net daily gain in weight during the feeding period. The 
slight difference was in favor of pasteurized milk. Hess (35), how- 
ever, has found that milk pasteurized for 30 minutes at 145° may 
cause, in infants, a mild form of scurvy, which yields readily to so 
simple a remedy as orange juice. 
The high-temperature heating of earlier days must not be confused 
with the low-temperature pasteurization of the present day. Many 
of the objections which have been raised to pasteurization have been 
founded on the observation of milk heated to high temperatures. 
However, the fallacy of the objections to pasteurization has been 
shown, through scientific research in the last few years, and as a 
result the value of the process has been firmly established. 
VALUE OF PASTEURIZATION 
From a sanitary standpoint, the value of pasteurization is of greatest 
importance when the general milk supply is under consideration. The 
pasteurization of milk, when the process is properly performed, affords 
protection from pathogenic organisms. Such disease-producing bac- 
teria as Eberthella typhi, and the dysentery bacillus, and other organ- 
isms of the typhoid-paratyphoid-enteritis group, Mycobacterium 
tuberculosis, and Corny ebacterium diptheriae, when heated at 140° F. 
for 20 minutes or more, are destroyed, or at least lose their ability to 
cause disease. 
Occasionally results are reported, such as those of Twiss (60) which 
again open the question of the destruction of certain pathogenic organ- 
isms by pasteurization. Using test organisms of the typhoid-para- 
typhoid group, she obtained results which indicated that not all these 
organisms were destroyed when they were heated in milk at 140° F., 
or even at 149°, for 30 minutes. Krumwiede and Noble (43), how- 
ever, using some of the same test organisms of the typhoid-para- 
typhoid group used by Twiss, found that the organisms did not sur- 
vive heating for 10 minutes at 140°. They further pointed out that 
the apparent heat resistance of the strains used by Twiss was due to 
the method of determining their thermal death point. 
According to Mohler (47), pasteurization offers protection against 
foot-and-mouth disease. He makes the following statement: 
Milk which has been pasteurized for the elimination of tubercle and typhoid 
bacilli will not prove capable of transmitting the disease (foot-and-mouth) to 
persons or animals fed with it. 
In view of the outbreak of foot-and-mouth disease in this country 
several years ago this statement is of importance. 
The abortus-like bacteria in the udders of healthy cows which were 
demonstrated by Evans (22) should also be considered in a discussion 
of pasteurization. She (23) found that both the pathogenic and lipo- 
lytic varieties could be destroyed by heating to 125° F. for 30 minutes 
or to 145° for 30 seconds. 
