18 BULLETIN 524, U. S. DEPARTMENT OF AGRICULTURE. 



Analyses made by the water laboratory of the Bureau of Chem- 

 istry of samples of salt collected from representative markets of 

 the United States showed but very small percentages of calcium 

 chlorid, magnesium chlorid, or sodium sulphate, the main impurity 

 being calcium sulphate. However, within a radius of 200 miles 

 from Cincinnati, a Salt is produced and consumed largely locally 

 that contains no sulphate and relatively large percentages of cal- 

 cium and magnesium chlorids (CaClg, 0.9 to 2.3 per cent; MgCls, 

 0.3 to 0.8 per cent). Table 14 shows that the effect of adding this 

 salt to butter is to increase greatly the percentage of calcium oxid 

 in the salt-free ash. An unneutralized butter might, therefore, 

 occasionallj'' be classed as neutralized if highly salted with salt con- 

 taminated with considerable calcium chlorid. Analyses of butter, 

 particularly if the butter is produced in the above locality, must be 

 scrutinized with special care if they show no sulphate. Magnesium 

 chlorid is associated with calcium chlorid in Ohio salt, and an 

 increase in the magnesium oxid percentage in butter salted with it 

 might be expected. Leach ^ states that the magnesium oxid content 

 of the ash of milk is only 2.42 per cent. The maximum amount of 

 magnesium oxid that could be present in 50 grams of butter, there- 

 fore, would be only about 2 milligrams. Any increase could be 

 regarded as due to impurities in the salt, and a high percentage 

 of calcium oxid in the salt-free ash would thus be explained. How- 

 ever, this salt is to be found only in a very limited area, and the 

 amount of butter affected thereby is exceedingly small compared 

 with the total product of the United States. The effect of calcium* 

 chlorid, therefore, may be considered practically negligible except in 

 a very few special cases. 



CALCIUM SULPHATE AND CALCIUM CHLORID. 



If both calcium sulphate and calcium chlorid are present, their 

 effect is cumulative. In Table 14 is shown a case where about 5 per 

 cent of salt which contained the maximum amount of calcium sul- 

 phate and calcium chlorid allowed in dairy salts ^ was used in salting 

 the butter. The percentage of calcium oxid in the salt-free ash 

 reached 30, but when the effect of the calcium sulphate was calculated, 

 though retaining the effect of the calcium chlorid, it dropped to 24, 

 1 per cent below the maximum. When 2.5 per cent of this salt of 

 maximum allow^ed impurity was employed, the percentage of calcium 

 oxid in the salt-free ash was only 25, without any correction for 

 calcium sulphate^ 



MAGNESIUM CHLORID. 



Should salt containing magnesium chlorid be used the percentage 

 of calcium oxid in the salt-free ash of the butter would be lowered 



1 Leach, Albert E., Food Inspection and Analysis, 3d ed., p. 128, New York, 1913. 



2 U. S. Dept. of Agriculture, Office of the Secretary, Circ. 19, Standards of Purity for 

 Food Products, p. 19. 



