Z BULLETIN 342, U. S. DEPARTMENT OF AGRICULTURE. 
VALUE OF PASTEURIZATION. 
From a sanitary standpoint, the value of pasteurization is of 
greatest importance when market milk is under consideration. The 
pasteurization of milk, when the process is properly performed, 
affords protection from pathogenic organisms. Such disease-pro- 
ducing bacteria as Bacillus tuberculosis, B. diphtherie, B. typhi, 
and other organisms of the typhoid-paratyphoid group, and the 
dysentery bacillus, when heated at 140° F. for 20 minutes or more 
are destroyed, or at least lose their ability to produce disease. 
Occasionally results are reported, such as those of Twiss (30),2 
which again open the question as to the destruction of certain patho- 
genic organisms by pasteurization. Using test organisms of the 
typhoid-paratyphoid group, she obtained results which indicated 
that there was not a complete destruction of these organisms when 
heated in milk at 140° F. and even at 149° F. for 30 minutes. Krum- 
wiede and Noble (24), however, using some of the same test organ- 
isms of the typhoid-paratyphoid group as used by Twiss, found that 
_ they did not survive heating for 10 minutes at 140° F. 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 (25), 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 
a few years ago this statement is of importance. 
The abortuslike bacteria in the udders of healthy cows which were 
demonstrated by Evans (15) may also be considered in a discussion 
of pasteurization. Although their sanitary significance has not been 
definitely established, it is interesting to observe that it was found 
by Evans (16) that both the pathogenic and lipolytic varieties could 
be destroyed by heating to 125° F. for 30 minutes or to 145° F. for 
30 seconds. 
Within recent years several epidemics of septic sore throat have 
been traced to milk. In some of these epidemics it was found 
possible, by pasteurization, to destroy streptococci which were iso- 
lated from throats of infected people and which were believed to 
be the infective agents. Pasteurization, properly performed, seems 
to protect against epidemics of this kind, but until the organism 
1See References to literature. 
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