80 MARKET DAIRYING 
Ill. DETECTION OF MILK ADULTERATION—WATERING AND 
SKIM MING. 
A knowledge of the methods of detecting watering and 
skimming of milk is in many cases of considerable value 
to milk dealers, even when the milk is bought on the fat 
basis. Where the milk is bought irrespective of its fat 
content, such a knowledge is simply indispensable for the 
welfare of the business. 
In normal milk ranging in fat from 3% to 5%, it is 
not difficult to detect a moderate amount of watering and 
skimming. We speak of normal milk because this means 
the milk from a full milking and excludes colostrum milk, 
milk from diseased cows and those far advanced in lacta- 
tion. Normal milk cannot be expected when cows are 
either only partially milked, diseased, or very far ad- 
vanced in lactation. 
The accuracy of determining the amount of watering 
and skimming becomes greater in proportion as the sam- 
ple represents more cows. For example, no sample of 
milk from a herd consisting of six or more cows has been 
known to average below 3% fat. For this reason any 
sample of milk testing below 3%, when taken from a 
herd, is to be looked upon with suspicion. On the other 
hand there are records of individual cows that show tests 
as low as 1.7% and as high as 8%. It is owing to these 
extreme variations in the composition of milk from indi- 
vidual cows, that small amounts of adulteration cannot 
be estimated with the same degree of accuracy in such 
milk as in herd milk. 
Detection of Adulteration. The general procedure in 
determining whether milk has been watered or skimmed, 
or both, is as follows: 
