4 BULLETIN 973, U. S. DEPARTMENT OE AGRICULTURE. 
can, because then all the milk from each producer can be mixed 
thoroughly and a fair sample taken. A two-compartment weigh can 
facilitates the weighing and sampling. 2 
From the time the milk is received and dumped it should be 
handled rapidly and should be exposed to contamination as little as 
possible. After the milk is weighed it usually passes through a 
clarifier or a filter to remove any dirt present. While large plants 
generally use a clarifier, very satisfactory results may be obtained 
with the use of a filter consisting usually of layers of cheesecloth 
and cotton, and considerable expense in equipment eliminated. 
There are also several types of mechanical filters now on the market 
Fig. 3. — Testing milk for butterfat content. 
PASTEURIZING AND COOLING. 
It is important that the milk be properly pasteurized, and a com- 
petent and reliable man should be assigned to this work. 
The primary purpose of pasteurization is the destruction of all 
pathogenic organisms in order to make the milk safe. Where milk is 
properly pasteurized, disease-producing organisms and nearly all 
other bacteria are destroyed, so that besides making the milk safe 
the keeping cmality is improved. 
In pasteurization two main objects are desired, namely, (1) de- 
struction of all disease-producing bacteria and a reduction of the total 
bacterial count of the milk; (2) economy in the use of heat, power, 
and labor. Unless the first is accomplished the second is of little 
account. 
k 2 For information on testing milk, plant operators are referred to Bureau of Animal Industry Circular 
A-12, "Chemical Testing of Milk and Cream," which may be obtained from the Superintendent of Docu- 
ments, Government Printing Office, Washington, D. C, for 10 cents; stamps not accepted. 
