40 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- 



