TESTING SKIM-MILK, WHEY, CHEESE, ETC. 85 



canted. Then the test is completed by adding lo cc. 

 of water, 17.5 cc. of sulphuric acid, and proceeding as 

 usual. Correct the fat-reading by multiplying by 18 

 and dividing by 7. 



METHOD OF TESTING FOR FAT IN INFANT 

 FOODS 



Some infant foods contain so much sugar that, like 

 sweetened condensed milk, it is impossible to use the 

 Babcock test unmodified. Cochran recommends a 

 method for the determination of fat in such cases, 

 which he has found very useful (Journal of the Amer- 

 ican Chemical Society, Vol. 2^, p. 908). A double- 

 tubed test-bottle is used, the larger tube reaching only 

 a short distance into the bowl of the bottle. 



To determine fat in sweetened condensed milk, make 

 a solution of the condensed milk in the manner given 

 above under (2). Of this solution put 17.5 cc. in the 

 test-bottle, add 9 cc. of 80 per cent, acetic acid and 

 9 cc. of strong sulphuric acid. Mix the acids and milk 

 and set the bottle in hot water until the mixture in 

 the bottle turns a coffee-brown color. Then remove 

 the bottle, cool, add 15 cc. of ether and mix thoroughly 

 with the liquid. The flask is again placed in hot wa- 

 ter and the ether allowed to evaporate. A layer of 

 fat will appear floating on the surface of the liquid. 

 By pouring hot water into the side tube, the liquid 

 fat is raised into the graduated tube, where its amount 

 can be read. The reading is corrected by multiplying 

 by 18 and dividing by 7. 



In the case of- powdered infant foods, like malted 

 milk, weigh 6 grams of the powder into the bottle. 



