CHEESE 67 



larger quantity of rennet and, especially, that cheese rich in 

 fat ripened more rapidly than skim-milk cheese. 



In addition to the fat and nitrogenous compounds just men- 

 tioned, cheese may contain a small amount of milk-sugar and 

 of lactic and other organic acids. There is present also a cer- 

 tain proportion of mineral matter, alkaline and earthy phos- 

 phates, along with any salt that has been added. Traces of 

 nitrates have been found. 



Skimmed milk is not infrequently used for the production 

 of cheese. Partially-skimmed milk is used in the preparation 

 of certain Dutch cheeses. Foreign fats, such as are used in 

 the manufacture of oleomargarin, are sometimes incorporated, 

 the article being known as "filled cheese." 



The ash of cheese consists largely of calcium phosphate and 

 salt. Mariani & Tasselli have estimated the total ash, 

 chlorin, calcium, and phosphoric acid in 15 samples of 

 cheese. The amounts of salts (calculated from the chlorin) de- 

 pend on the mode of salting. The proportion of phosphoric 

 oxid was always greater than that necessary to form trical- 

 cium phosphate, ranging from 1.07 and 1.08 equivalents of 

 phosphoric anhydrid to calcium oxid in cheese made from 

 sour milk to 1.56 to i in Gorgonzola, 1.67 to i in skim-milk 

 cheese, and 1.75 to i in Edam cheese. The largest quanti- 

 ties of calcium and phosphoric oxid were found in sheep's- 

 milk cheese and in cheese made from sour milk, whence it 

 follows that acidity does not prevent the precipitation of cal- 

 cium phosphate in the curds. The excess of phosphoric oxid 

 obtained was attributed to acid phosphates. 



The salt in cheese usually ranges between i and 4 per cent. 



Analytic Methods. — The analytic points usually deter- 

 mined in regard to cheese are water, fat, casein, ash, the pres- 

 ence of fats other than butter-fat, and coloring-matters. 



In addition to this, especially in comparing the quahties of 



