198 The Analysis of Dairy Produce [329-333 



sooner, all other conditions being equal, than one containing 

 smaller quantities. 



The fat should not fall below 80 per cent. 



CHEESE ANALYSIS 



The determinations ordinarily made in cheese analysis are 

 water, fat, casein (nitrogenous matter), and ash. 



329. Water. — Grate a piece a cheese on a bread grater 

 until a sufficient quantity of gratings has been collected, then 

 weigh out 5 grams of the material in a dish, and heat in the 

 steam oven until no further loss takes place. Loss of weight 

 = moisture. 



330. Fat.— This is estimated in Soxhlet's apparatus as 

 shown in fig. 38 and described in paragraph 140, but the special 

 precaution is necessary that . the cheese must be quite dry. 

 The best method is to use the portion in which the moisture 

 has been determined, removing it completely from the drying 

 dish to a cartridge case of filter paper, and extracting as usual. 



331. Casein.— Usually estimated by difference. Should 

 a direct determination be necessary, it may be made by esti- 

 mating the nitrogen by the acid process (paragraphs 92-95) in 

 about half a gram of the cheese, and multiplying the percentage 

 of nitrogen by 6*25. 



332. Ash may most easily be determined in the portion 

 which has been extracted, or 5 grams may be weighed into a 

 platinum dish, and burned over an Argand at as low a tempera- 

 ture as possible. 



The salt may be determined by dissolving the ash and 

 titrating with decinormal AgN0 3 . 



The phosphates may be determined by the method 

 described in paragraph 246. 



333. Adulteration of Cheese.— Margarine is. frequently 



