PRESENT STATUS OF PASTEURIZATION OF MILK. 3 
of development can not replace that of pasteurization on a com- 
mercial scale. 
EXTENT OF PASTEURIZATION IN THE UNITED STATES. 
Pasteurization, when first practiced by milk dealers in this country, 
was carried on secretly, and, except as a means of preserving the 
milk, was regarded by them as a process of no value. As the prac- 
tice became more general the subject of pasteurization was studied, 
and its value as a means of destroying disease-producing bacteria 
was recognized. In consequence of the recognition of the merits of 
the process there has been during the last 10 years a rapid increase 
in the quantity of milk pasteurized, particularly in the larger cities. 
Jordan (3) states that 10 years ago only about 5 per cent of the 
milk supply of New York City was pasteurized, as compared with 
about 40 per cent in 1912 and 88 per cent in 1914. In Boston, in 1902, 
very little milk was pastenrized, while at present 80 per cent is so 
treated, and in many of the smaller cities there have been correspond- 
ing increases in the quantity of milk pasteurized during the last few 
_ years. 
The general tendency in this country to-day is toward the pas- 
teurization of all market milk, with the exception of certified and 
- inspected milk from tuberculin-tested herds. Some idea of the extent 
of pasteurization may be gained from Table I. The figures? were 
supplied by the milk-investigations section of the Dairy Division 
and were obtained from replies to circular letters sent to health 
officers. 
Taste I.—Hetent of pasteurization of milk in cities in the United States. 
Number of| More than 11 to 50 per} Oto 10 per 
Population of cities. cities an- 50 per cent | cent pas- | cent pas- None pas- 
swering pasteur- : F teurized. 
question. ade teurized. | teurized. 
Pronentiam o00;00022..02- 22. - fc ce sie. oes 9 7 2 0 0 
HOOFOOIEFO 500/000 RE aes ot yeh sd deca 40 12 20 6 2 
THOOI LoL ete ea a esau ae ae i 19 5 8 4 2 
SOO Wey VE UU EE Seer sees anne ace eene sum 30 4 15 6 5 
BOO 50:000. 555262, 5- 220 5025-8 Be era oie 78 13 31 12 22 
BP OOO O25 0008 5 oe os Fee ess ee 168 10 40 18 100 
ROTM al es Se hae cel is eae as Seas mt 344 51 116 46 131 
Tt will be seen that of nine cities with a population of more than 
800,000 each, in seven more than 50 per cent of the milk is pasteur- 
ized; in fact, the proportion is much higher, as Table II shows. 
Since these figures were obtained the per cent of milk pasteurized 
has probably increased in these cities. 
1 These figures were obtained through the kindness of Mr. Ernest Kelly and Mr. L. B. 
Cook. 
