650 
inert it is a limitation, not a disadvantage of the process. If heat- 
resisting poisons are present in milk, the raw product will be quite as 
toxic as the heated, probably more so, for the heat may check the fur- 
ther production of such substances by its destructive action upon 
bacteria. 
At first, “sterilization” at or above the boiling point was attempted. 
It was soon shown that it was exceedingly difficult to sterilize milk 
on account of the resistant spores, and further, that a high degree of 
heat is not necessary. A more precise knowledge of the objects to be 
attained has gradually resulted in lowering the temperature and 
shortening the time. Temperatures varying from 95° to 60° C., and 
periods varying from a moment to two hours, have been variously 
recommended for the pasteurization of milk. As a rule the control- 
ling factor is the thermal death point of the tubercle bacillus. 
The temperature and time determined by various authorities for 
milk pasteurization follows: 
Authorities. 
Year. 
Tempera- 
ture (°C.). 
Time 
(min- 
utes) . 
Freeman « 
1898 
68 
30 
Freeman i> 
1907 
60 
40 
Forster “ 
1892 
70 
5-10 
Smith, Th.d 
1899 
60 
20 
Oppenheimer < 
1899 
70 
30 
Hippius / 
1905 
60 
60 
Bitter g 
1890 
68-69 
30 
Hesse ^ 
1900 
60 
15-20 
Russell Hastings t. 
1900 
60 
20 
“Freeman, Arch. Pediat., N. Y. (1898), v. 15, p. 514. 
" Freeman, Jour. A. Med. Assn., Vol. XLIX, Nov. 23, 1907, 21, p. 1740. 
“Forster, Hyg. Rundschau, Berl. (1892), v. 2 (20), 15. Okt., p. 872. 
" Smith, Th., J. Exper. Med., N. Y. (1899), v. 4, p. 233. 
“ Oppenheimer, Munch, med. Wchnschr. (1899), v. 46, p. 1462. 
t Hippius, Jahrb. f. Kinderh. (1905), v. 61, pp. 365-384. 
Bitter, Ztschr. f. Hyg., Leipz. (1890), v. 8, p. 255. 
"Hesse, Ztschr. f. Hyg., Leipz. (1900), v. 34, p. 347. 
^ Russell and Hastings, 17 Ann. Rep., Agric. Exper. St., Univ. Wis. (1900), p. 170. 
In view of certain differences of opinion concerning the tempera- 
ture and time of milk pasteurization, the definition still lacks com- 
pleteness. Therefore the misconceptions and confusions concerning 
the use of the term “ pasteurized milk ” have added to the prejudice 
against the process. We should protest against a word which means 
a generality and again insist upon all pasteurized milk being prop- 
erly labeled with the degree of heat^ the period of time^ and also with 
the date on which it was subjected to the process. 
So far as we may conclude from the evidence at hand, the heating 
of milk to 60° C. for twenty minutes destroys pathogenic micro- 
organisms without injuriously affecting its composition or quality and 
