ADULTERATION OF MILK 193 



the density again determined. Another i c.c. of water 

 is then added as before, and the process repeated three 

 or four times. It will be found that the density regularly 

 decreases as the proportion of water is increased, and 

 the results obtained should be plotted in the form of 

 a curve showing the relation between percentage of 

 added water and density. From the curve can be 

 obtained the percentage of water necessary to give a 

 density for diluted skimmed milk of the same value 

 as that possessed by the original whole milk before 

 skimming. 



Detection of Added Water. — The addition of water to 

 milk will lead to a decrease in the density, the fat 

 contents and the total solids, but the proportion of 

 fat in the total solids will not have undergone any 

 alteration. 



Milk should generally be suspected of having been 

 adulterated by the addition of water, if at the same 

 time — 



the density is below . . 1-028 



the total solids are below . 10-3 per cent. 



Detection of Removal of Cream. — The removal of 

 cream from milk or the addition of skim milk will 

 generally lead to a certain increase in the specific 

 gravity, but will always have a marked effect on the 

 percentage of fat, and especially on the proportion of 

 fat in the total solids. The solids not fat will not 

 generally have been decreased. 



Milk may come under suspicion of having been 

 skimmed, or diluted with skim milk, if the percentage 

 of fat in the total solids is below 19-9, or — 



the fat is below . . .2-5 per cent, 

 the solids not fat are above . 8-0 „ 



Detection of Simultaneous Removal of Cream and 



N 



