ON MILK AND MILK-TESTING 6l 



How may the fat in sweetened condensed milk be 

 determined by the Babcock test? 



The method devised by Farrington is practically 

 as follows: 



Dissolve 40 grams of the condensed milk in 100 

 c. c. of water. Measure into a milk-testing bottle 

 a Babcock pipette full to the mark of this sokition. 

 Add about 3 c. c. of the sulphuric acid used in 

 testing milk and shake the mixture vigorously. 

 The coagulated casein incloses the fat and they are 

 thrown down together by whirling in the machine 

 at a high speed and a temperature of 200° F. The 

 liquid containing much of the sugar is carefully 

 poured off. Ten c. c. of water is then added and 

 the mass of curd is broken up and thoroughly 

 shaken with the water to remove more sugar ; 3 c. c. 

 of acid is again added and the bottle whirled as 

 before. The liquid is again poured off. The test 

 is now completed by adding 10 c. c. of water and 

 17.5 c. c. of sulphuric acid and proceeding as in the 

 fat test for milk. Multiply the fat reading by 3.2 

 to obtain the per cent. 



C. B. Cochran proposes the following method for 

 fat in sweetened condensed milk: 



" Weigh out 25 g^ams of the sample, dissolve in 

 water and make up to 100 c. c. Transfer 6 c. c. to 

 a double tube milk flask provided with a small bore 

 tube graduated to give percentage of fat for 5 c. c. 

 of milk. Add 4 c. c. of ether and 4 c. c. acetic acid 

 (80 per cent or more absolute acid). Acetic acid 

 of this strength will dissolve the curd, but has no 

 effect on the sugar. Place the flask in a vessel of 

 warm water and heat until the ether is expelled. 

 A layer of milk fat will now be seen floating on a 



