BULLETIN 342, U. S. DEPARTMENT OF AGRICULTURE 
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 de- 
struction of certain pathogenic organ- 
isms by Pasteurization. Using test 
organisms of the typhoid-paratyphoid 
group, she obtained results which in- 
dicated 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. Krumwiede 
and Noble (24), however, using some 
of the same test organisms 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 ap- 
parent heat resistance of the strains 
used by Twiss was due to the method of 
determining their thermal death point. 
According to Mohler ro 5), Pasteuri- 
zation offers protection against foot- 
and-mouth disease. He makes the fol- 
lowing 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 ani- 
mals fed with it. 
In view of the outbreak of foot-and- 
mouth disease in this country a few 
years ago this statement is of import- 
ance. 
The abortuslike bacteria in the ud- 
ders of healthy cows which were 
demonstrated by Evans (15) may also 
be considered in a discussion of Pas- 
teurization. Although their sanitary 
significance has not been definitely es- 
tablished, it is interesting to observe 
that it was found by Evans (16) that 
both the pathogenic and lipolytic va- 
rieties could be destroyed by heating 
to 125° F. for 30 minutes or to 145° 
F. for 30 seconds. 
Within recent years several epidem- 
ics 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 isolated from throats of 
infected people and which were be- 
lieved to be the infective agents. 
Pasteurization, properly performed, 
seems to protect against epidemics of 
this kind, but until the organism 
which causes the disease is definitely 
known it is impossible to say that it 
affords absolute protection. 
2 See references to literature. 
Since it is quite generally believed 
that the streptococci are the causative 
agents of septic sore throat, the abil- 
ity of certain of this group of organ- 
isms to stand temperatures above that 
of Pasteurization naturally presents a 
grave situation. If pathogenic strep- 
tococci are "able to survive the usual 
process of Pasteurization, the value of 
the process, from a sanitary stand- 
point, is materially lowered. 
Experience with the use of properly 
Pasteurized milk and the determina- 
tion of the thermal death point of 
pathogenic streptococci by various in- 
vestigators indicate very clearly, how- 
ever, that the thermal death point of 
these organisms is relatively low and 
that they are readily destroyed by 
proper Pasteurization. Thus Ham- 
burger (17), who studied the epidemic 
of septic sore throat in Baltimore in 
1912, traced this epidemic to a certain 
milk supply. Advice was given to boil 
all milk, and the dairy connected with 
the epidemic raised the temperature of 
its flash Pasteurization to 160° F. : 
then it changed to the holder process, 
by which the milk was heated to 145° 
F. and held for a period of 30 min- 
utes. The cases of sore throat that 
followed were neither so severe nor so 
numerous and did not follow the milk 
supply, but appeared to have been 
transmitted from individual to indi- 
vidual. Hamburger (IS) also found 
that a streptococcus isolated from a 
patient having a case of sore throat 
was killed by heating in milk at 145° 
F. for 30 minutes. 
Again, Capps and Miller (12), who 
studied the Chicago epidemic of septic 
sore throat, traced it to a dairy where 
the milk was Pasteurized by the flash 
process at 160° F. On certain dates 
they found that there was a pro- 
nounced failure to Pasteurize, and fol- 
lowing these dates there were 
outbreaks of septic sure throat. These 
authors believed that the final respon- 
sibility for the epidemic rested on the 
inadequate and unreliable Pasteuriza- 
tion. They state that the absolute 
protection of the children of the 
Michael Reese Hospital from infec- 
tion by efficient Pasteurization demon- 
strates this point. Bray (11). who 
studied an epidemic of tonsillitis of 
tuberculosis patients, traced the epi- 
demic to a milk supply of one farm 
where a carrier presumably infected 
the milk. Forty cases of tonsillitis 
resulted among 400 people. As soon 
as the epidemic broke out the milk 
was Pasteurized, and from that time 
only one case appeared. 
