72 MILK PRODUCTS 
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The full analysis of sweetened condensed milk 
is difficult, and many of the published figures are 
erroneous. The sucrose interferes with the ex- 
traction of the fat by solvents. The same 
difficulty occurs in the analysis of some prepared 
infant-foods, such as mixtures of milk with malt 
and glucose. 
For the general operations, a portion of the 
well-mixed contents of a freshly opened can 
should be accurately weighed, diluted with a 
known amount of water, and well mixed, from 
which mass the portions for analysis may be 
taken and the results calculated to the original 
sample. 50 grams mixed with 150 c.c. of water 
will be a convenient quantity. For the polar- 
imetric determination of lactose, a special pro- 
cedure will be necessary; but for determination of 
solids, ash, total proteins, and total reducing 
sugars, the examination may be made as with 
ordinary milk upon this diluted sample. 
Fat.—The Adams method is not satisfactory 
under ordinary conditions, owing to the sucrose. 
The Rése-Gottlieb method is now largely used 
and generally approved. The following descrip- 
tion is given by Bigelow and Fitzgerald: 
Weigh from 4.5 to 5.0 grams evaporated or 
condensed milk into a Rése-Gottlieb tube, add 
water to make about 11 grams and 14% to1¥ 
