46 MILK ANALYSIS 



due to preparation from closely-skimmed milks. Preserva- 

 tives (other than cane-sugar) and coloring-matters are rarely 

 used, nor is it likely that foreign fats will be present. 



ANALYSES OF COMMERCIAL CONDENSED MILKS 



Total 



Solids. Fat. Proteids. Lactose. Sucrose. Ash. Analyst. 



36.7 10.5 9.7 14.2 none 2.1 Pearmain and Moor 



31.2 9.6 9.2 lo.g none 1.5 F. J. Aschman 



28.1 8.8 8.5 9.8 none 1.8 F. J. Aschman 

 78.4 9.3 9.1 13.4 40.4 2.0 F. J. Aschman 



74.2 9.0 9.3 10.2 43.7 1.9 F. J. Aschman 

 70.9 1.4 11.4 14.6 41.9 1.6 Pearmain and Moor 



The sucrose in the last sample was determined by difference. 



The analysis of unsweetened condensed milks is conducted 

 as with ordinary milk, the sample having been previously 

 diluted with several times its weight of water heated to boil- 

 ing, cooled, and made up to a defiriite volume. The fat may 

 be readily estimated by the L-B. process. 



The full analysis of sweetened condensed milk is difficult, 

 and many of the published figures are erroneous. The cane- 

 sugar interferes with the extraction 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 con- 

 tents 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 re- 

 sults 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 procedure will be 

 necessary; but for determination of solids, ash, total proteids, 

 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. Geisler substituted petro- 



