14 TESTING AND HANDLING OF MILK AND CREAM 
and sampled by the McKay sampler, or some other recognized sampler 
that will secure a representative sample. Always mix by pouring, un¬ 
less the McKay or a similar sampler is used. 
The ordinary stirring rod generally used will not get an accurate 
average sample unless pouring is resorted to in addition. 
Cream that is frozen or lumpy should be heated to no degrees in 
a water bath and then thoroughly mixed, stirred and poured. It should 
remain in the water bath until the body of the cream has become 
smooth, free from lumps and of a uniform texture. After such cream 
has become free and smooth it may be sampled the same as other cream. 
Milk may be sampled the same as cream, with the exception that 
only one pouring is required by law. However, additional mixing is 
often necessary and always beneficial toward securing an accurate 
sample. 
Composite Samples .—“In sampling milk or cream, from which 
composite tests are to be made to determine the per cent of butter fat 
contained therein, such samples or sampling shall not he lawful unless 
a sample be taken from each weighing and the quantity thus used 
shall be proportioned to the total weight of the cream or milk samples." 
The sampling should be done the same as for taking samples for other 
tests, with the exception that the composite sample must be proportional 
to the quantity of cream from which it is taken. That is, take only half 
as large a sample from a half can of cream as from a full can. The 
samples taken from all the cans of cream should be mixed together and 
warmed in a water bath and a test made from them the same as from 
other samples. This test multiplied by the number of pounds of cream 
sampled, will show the number of pounds of butter fat in the total 
amount of cream sampled. 
Tin's method of making a composite test of each shipment of cream 
should be used as a check on the day’s business, and as an aid toward 
checking out with the creamery. The amount of rinse water used in 
the cans will not affect the total pounds of butter fat, since the slight 
lowering of the test by the addition of the water will exactly com¬ 
pensate the increase in weight. 
The value of such a check on shipments rests entirely upon the 
care given in taking the samples or sample, providing the test is com¬ 
pleted by the usual methods. 
Care of Samples —If samples are allowed to stand any length of 
time before testing, they should be tightly covered in order to prevent 
evaporation. The use of common milk bottle caps in the tops of the 
small sample jars now generally used is an effective seal. Where it is 
absolutely necessary for tests to stand many hours, it is best to add 
some preservative to prevent souring and curdling. A few drops of 
formalin or corrosive sublimate is good, but all such preserved samples 
should be emptied in the waste as soon as tested, for corrosive sublimate 
is poisonous and formalin also if very much is used. 
