76 MILK PRODUCTS. 



in a satisfactory manner when the curd is produced by 

 the action of acids or neutral mineral salts, possibly 

 because these agents interfere with the action of the 

 microbes and enzymes on which the ripening depends. 

 Skimmed milk is not infrequently used for the pro- 

 duction of cheese, and foreign fats such as are used 

 in the manufacture of oleomargarin are sometimes 

 incorporated. 



The analytical points to be determined in regard to 

 cheese, are amounts of water, fat, casein, ash, the 

 presence of fats other than butter-fat and coloring mat- 

 ters. 



Care should be taken to select for analysis a sample 

 which represents the average composition of the en- 

 tire cheese. A thin section, reaching to the centre, is 

 preferable, and portions from various parts of this 

 should be cut fine and mixed. This should be done 

 with as little exposure to air as possible, to avoid loss 

 of water. 



The following methods for water, fat, ash and casein 

 are those provisionally adopted by the Association of 

 Official Agricultural Chemists. 



^A^ate^. — From 5 to 10 grams of cheese should be 

 taken, and placed in thin slices in a weighed plat- 

 inum or porcelain dish which contains a small quantity 

 of freshly ignited asbestos, to absorb the fat which 

 may run out of the cheese. The mass is then heated 

 in a water oven for ten hours, and weighed; the loss 

 in weight is to be considered as water. 



Ash. — The dry residue from the water determina- 



