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 qualities of 



