100 Testing Milk and Its Products. 



bottle chamber of some machines, or by means of a 

 valve and pipe which vyill allow steam to be turned di- 

 rectly into the test bottle chamber. After this first 

 whirling the bottles are taken from the tester 

 and by being careful not to break the lump of curd 

 nearly all the whey or sugar solution can be poured out 

 of the neck. Ten cc. of water are then poured into the 

 test bottle and the curd is shaken up with it so as to 

 wash out more of the sugar. Three cc. of acid are now 

 added as before and the test bottle whirled a second 

 time. The whey is again decanted and this second 

 washing removes so much of the sugar that what re- 

 mains will not interfere •\^'ith testing in the usual way. 

 The curd remaining in the bottle after the second wash- 

 ing is shaken up with ten cc. of water; the water-emul- 

 sion of the curd is then cooled; the usual amount, 17.5 

 cc, of sulfuric acid is added, and the test completed in 

 the same way as when milk is tested. The amount of fat 

 obtained in the neck of the test bottle is calculated to 

 the weight of condensed milk taken. ^ 



io8. Ice cream. Methods for determining the per 

 cent, of fat in ice cream have been worked out by 

 Holm,- Howard'' and others. Holm recommends the 

 use of a mixture of equal parts of hydrochloric and 

 glacial acetic acid, in the place of sulfuric acid, as the 



'The Gottlieb metliod gives very satisfactory results with both cheese 

 and condensed milk (see 254). See also Jr. Ind. and Eng. Chem., 

 1912, p. 672. For method of analysis of desiccated milk, milk powder, 

 etc., see ibid., 1912, p. 644. 



' Report Dept. of Health, City of Chicago, 1900, p. SO. 



^Journ. Am. Chem. Soc, 1907, p. 16. Methods of analysis of ice 

 cream have also been proposed by White, (Penna. exp. sta., rept. 1910, 

 p. 243), Baird, (N. Y. Prod. Rev., Feby. 26, 1013), and Halvorsen, 

 (Jr. Ind. and Eng. Chem., ^> (1913), p. 403). 



