THE MILK SUPPLY OF CHICAGO 173 
necessary for the condenseries to absorb this surplus, which 
sometimes works a hardship on that industry. 
PRODUCTION 
At the present time 98 per cent of the milk consumed in 
Chicago is pasteurized, according to the Chicago Health De- 
partment. The other 2 per cent is certified milk. A clause 
in the city ordinance provides for the sale of raw inspected 
milk, but none is sold, unless certified milk is included under 
this head. 
All pasteurized milk has been heated in a ‘‘holding system’’ 
since 1914. A minimum temperature of 140° F. with a min- 
imum time of 20 minutes is required. Previous to 1914, the 
“‘Hash’’ system was used almost exclusively. 
The largest dealers in the past have advertised the fact 
that their milk was bottled in the country, and at the present 
time, this practice is maintained by them, although one of 
the largest companies has erected and operated a modern plant 
within the city limits for the past four years. 
The plants located in the country are known as “‘bottling 
plants’’. They are situated as a rule near a railroad track. 
The milk is delivered at these plants, by the farmers them- 
selves, between 6:30 and 11 A. M., depending on the season 
of the year. In summer deliveries are made early, and 
in winter late. It is a ruling of the milk distributors that 
the milk cans be covered with canvas during transit from farm 
to plant. ; 
The milk is cooled by the farmer to 60° F. or below, usually 
by placing the cans in a tank of cold running water. After 
delivery at the plant, the cans are thoroughly washed and 
steamed before they are returned to the farmers. Immed- 
iately after delivery, the milk is pasteurized and cooled to 
45° F. The milk is then filled into glass bottles; no single 
service packages are used to any extent. All milk for the 
retail trade has been bottled since 1891, and that for the 
wholesale trade is put up in 8 or 10 gallon cans. 
Some of the bottling plants are equipped with separators 
and separate their own cream for the trade. The skim milk 
