46 MARKET DAIRYING 
venient and efficient, and, in many cases, the cheapest 
method of cooling milk and cream. The brine may be 
reduced to any temperature desired with a mechanical 
refrigerating machine. It is forced through the cooler 
with a pump, in the same manner as ordinary ice water. 
With the latter it is difficult to cool milk and cream below 
40° F., while with the brine the temperature is easily re- 
duced to 34° F., at which milk and cream remain prac- 
tically without change. Such a low temperature is espe- 
cially desirable in shipping milk and cream. When cream 
leaves the dairy at a temperature near freezing, it may 
be shipped in an ordinary can wrapped with a felt jacket 
a distance of 500 miles or more in warm weather without 
undergoing a noticeable change in either flavor or acidity. 
Precautions in Cooling; © While cooling milk or 
cream, the room should be kept damp, especially the 
floor. This will keep down any dust that may be in the 
room and thus keep it from getting into the milk. 
Draughts should be avoided during cooling for the same 
reason. In this connection it is well to remember that 
the real harm is not so much in the dust particles them- 
selves as in the many bacteria which usually adhere to 
them. 
Where coolers are left exposed to the air of the room 
after they have been cleaned and sterilized, they should 
be rinsed off with boiling water just before using. 
It is important also to use a reliable thermometer. 
Ordinary cheap thermometers often read two to six de- 
grees too high or too low. A standard thermometer 
should be on hand by which the cheaper ones may be 
standardized. 
Never Use Ice in Milk or Cream. Adding ice di- 
rectly to milk and cream is a pernicious, though not un- 
