98 Testing Milk and Its Products. 



with the water. A few cc. of acid will aid in this mixing 

 and disintegration, the process being hastened by placing 

 the bottles in tepid water. When all lumps of cheese 

 have disappeared in the liquid, the full amount of acid 

 is added, and the test completed in the ordinary man- 

 ner. 1 



The per cent, of fat in the cheese is obtained by mul- 

 tiplying the reading of the fat column by 18 and divid- 

 ing the product by the weight of cheese. The weighing 

 of the cheese and the reading of the fat must be done 

 very carefully, since any error introduced is more than 

 trebled in calculating the per cent, of fat in the cheese. 



106. Condensed milk. The per cent, of fat in un- 

 sweetened condensed milk can be obtained by weighing 

 about 9 grams into a test bottle and proceeding in ex- 

 actly the same way as given under testing of cheese. 

 It is not necessary to warm the condensed milk in the 

 test bottles, since this is readily dissolved in water. 

 Enough water should be added to make the total volume 

 of liquid in the bottles 15 to 18 cc. 



If a scale is not available for weighing the sample, 

 fairly accurate results may be obtained by diluting the 

 condensed milk with water (1:3), and completing the 

 test in the ordinary manner. When this is done, the 

 results must be corrected for the dilution which the 

 sample received. 



Hunziker 2 recommends adding hot, dilute sulfuric 

 acid solution after the first whirling, in the analysis of 

 unsweetened condensed milk (sulfuric acid and water, 



1 See also Sammis, Journ. Ind. and Eng. Chem., I, p. 604. 



2 Ind. expt. sta., bull. 134. 



