DAIRY HUSBANDRY 
39 
EXERCISE NO. 30 
Object: To become acquainted with adulteration formulae and their verifica¬ 
tion. 
Procedure: A number of formulae have been developed for calculating 
the extent of adulteration, if skimming or watering, or both 
have been practiced. 
A. Obtain the lactometer reading and the fat test of a one pint 
sample of normal milk. 
B. Divide the pint of milk into two equal parts and proceed as 
follows: 
(1) Add water to one part at the rate of 5 cc. per 100 cc. of 
milk, and test as “A” above. 
(a) On the basis of the control sample, calculate the per 
cent of water added to the original milk by the following 
formula: 
100 X control for SNF 
-100 
SNF in suspected sample 
(b) On the basis of the legal standard for SNF, calculate 
the per cent of water added to the original milk by the 
following formula: 
lOOXleg. standard for SNF 
--- 100 . 
SNF in suspected sample 
(c) Add skimmilk, a little at a time, from a graduate until 
the lactometer is again as in A above. Record the 
amount of skimmilk used. 
(2) To the second half pint add water at the rate of 10 cc. per 
100 cc. of milk and proceed exactly as for the first pint. 
Observations: 
Sample 
% 
fat 
Corrected 
Lactom¬ 
eter 
reading 
% 
SNF 
% 
water 
added 
cc. skim¬ 
milk 
added 
% adull 
teration 
Formula 
A 
Formula 
B 
1 
2 
a 
b 
3 
a 
b 
Conclusion: 
