S82 Missouri Agricultural Report. 



3. Amount the butter is worked — 



If worked much the water may be worked out and the butter 

 left dry, or with only 10 per cent, of water, while less working 

 'Or working in water may leave a wet butter, or one containing 

 as high as 20 per cent, water. 



4. Size of churn and amount of cream — 



If the churn is too large for the amount of cream, consider- 

 able cream may be lost by sticking to axis of the churn. This is 

 especially liable to occur with thick cream in small quantities. 



5. Accuracy of the scales — 



On small amounts of butter the degree of accuracy of the 

 scales used may introduce an apparent discrepancy. 



THE ADULTERATION OF MILK AND ITS DETECTION.* 



Compositio7i of Milk — Before entering into a discussion of the 

 adulteration of an article, it is necessary that the normal compo- 

 sition of that article be first understood. Milk is a complex fluid, 

 made up of several very dissimilar substances. Its composition 

 varies according to the breed of the animal. Some breeds of cows 

 give milk much richer in fat and samewhat richer in other solids 

 than others. Not only is there a difference between breeds, but the 

 milk from different individuals of the same breed will vary consid- 

 rably, and a cow giving milk which tests 4 per cent, fat, when she 

 is fresh, will usually give milk testing 4V2 per cent, to 4,8 per cent, 

 toward the end of her lactation period. When cows are nearly dry 

 their milk is richer in all solids, especially in fat, than it is when 

 they are fresh. Dry feed also has a tendency to produce a slightly 

 richer milk. 



Milk Solids — When milk is evaporated to dryness the water 

 is evaporated, and the milk solids are obtained. Milk solids are a 

 mechanical mixture of fat, casein, albumen, milk, sugar and ash. 

 Normal milk contains about 13 per cent, of solid matter and 87 

 ; per cent, water. Some samples contain as low as 12 per cent, sol- 

 ids, with 88 per cent, water ; others as high as 14 per cent, solids, 

 with 86 per cent, water. 



Milk Fats — Average milk contains about 31/2 per cent, of fat. 



'Some normal samples may contain 3 per cent, or less, while others 



may contain 6 per cent, or more. The fat in milk is not present 



in solution, but in suspension in the form of minute globules. 



These milk fat globules are about 1/5,000 of an inch in diameter. 



(•In preparing the following pages on adulteration free use has been made of ' ' Dairy 

 •'Ohemistry" by H. Snyder.) 



