CHAPTER X 



MILK BY-PRODUCTS 



98. Uses of By-products. In the manufacture of 

 butter and cheese the by-products are skim milk, 

 buttermilk, and whey. These products are used 

 mainly for animal-feeding purposes and have a high 

 food value. Also from the by-products a number 

 of commercial articles are prepared. From whey, 

 milk sugar is manufactured, and from skim milk, 

 proteids are precipitated and prepared for commer- 

 cial uses. 



99. Skim Milk Composition, Value, and Use. In 

 the manufacture of butter, about 80 per cent of skim 

 milk is obtained. The chief ingredients of skim 

 milk are casein, albumin, ash, and milk sugar. Be- 

 cause of the removal of the fats in skimming, the 

 solids not fat are usually present in the skim milk 

 in slightly larger proportions than in the whole 

 milk. Skim milk is characterized as a food of high 

 proteid content and it is valuable in combination 

 with other foods that are lacking in protein, par- 

 ticularly for the feeding of young and growing ani- 

 mals. Average skim milk contains about 9.75 per 

 cent of solid matter, of which 3.7 pounds are casein 

 and albumin, and 5.15 pounds are sugar, the remain- 



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