DETECTION OF LIME USED IN DAIEY PRODUCTS. 3 
While it is probable that the percentage of calcium oxid in the 
ash of pure cream and butter would correspond closely to the figures 
quoted above, it is important to prove this point before proceeding 
with the interpretation of analyses of commercial milk products to 
determine whether lime may have been added. 
METHODS OF ANALYSIS. 
Samples of milk, buttermilk, or cream require no particular prep- 
aration for analysis. All samples of butter analyzed in this in- 
vestigation were prepared in the following way: About 1 pound 
of butter was melted at as low a temperature as possible in a well- 
stoppered, wide-mouthed bottle and then cooled. The melted fat, 
curd, water, and salt were violently shaken together before and 
during the "setting" of the butter. If the sample subsequently is 
kept cool, it will not leak buttermilk, thus causing variations in 
sampling. 
In order to prove the addition of lime to dairy products a careful 
analysis of the ash is essential. To determine total ash, 10 grams of 
milk, cream, or butter are weighed out in a platinum dish, the water 
evaporated on a steam bath or air oven, the fat then burned off, and 
the dish heated in a muffle at a low heat until a white ash remains. 
The water must be completely evaporated before the fat is ignited, 
otherwise there will be loss by spattering. In the case of salted but- 
ter, after weighing the ash add dilute nitric acid and determine the 
sodium chlorid by precipitation with silver nitrate. All results 
reported in this bulletin were determined gravimetric ally, with the 
exception of alkalinities. Unless the percentage of salt is more than 
5 it is best determined without taking an aliquot. The difference 
between the total ash and the sodium chlorid in the ash is the salt- 
free ash. In duplicate determinations there may be a noticeable 
difference in the total ash, but the percentages of salt-free ash agree 
very closely. Examples of some of the results obtained are given 
in Table 2. No effort was made to select especially favorable results. 
Table 2. — Agreement in percentages of salt-free ash in dairy products. 
Sample 
Total 
Salt. 
Salt-free 
Sample 
Total 
Salt. 
Salt-free 
No. 
ash. 
ash. 
No. 
ash. 
ash. 
Per cent. 
Per cent. 
Per cent. 
Per cent. 
Per cent. 
Per cent. 
1 
2.117 
2.004 
0.113 
6 
3.430 
3. 285 
0.112 
2.066 
1.956 
.110 
3.400 
3.258 
.142 
2 
3.887 
3.735 
.152 
7 
3.840 
3.694 
.146 
3.863 
3.718 
.145 
3.840 
3.700 
.140 
3 
4.860 
4.660 
.200 
8 
4.784 
4.654 
.130 
4.779 
4.577 
.202 
4.758 
4.629 
.129 
4 
4.768 
4.647 
.121 
9 
4.780 
4.620 
.160 
4.640 
4.518 
.122 
4.808 
4.644 
.164 
5 
4.847 
4.675 
.172 
10 
4.822 
4. 721 
.101 
4.870 
4.693 
.177 
4.753 
4.655 
.098 
