634 ANNUAL REPORT OF THE Off. Doe. 



in the soliditied mass just where they hapxjen to be at the iustant. 

 coagulation takes place. When the curd k*iile passes through the 

 solid mass, large numbers of lat-globules are exposed on every 

 cut surface, and many of these fall into the whey and so are not 

 retained in the cheese. 



What conditions contribute to loss of milk-fat in cheese-making? 

 In abnormal milk, when the casein is small in amouut in propor- 

 tion to fat or when it fails to coagulate normally, there are extra 

 losses of fat. Any coudiUon that interferes with complete coagu- 

 lation by rennet, such as marked dilution of milk by water, presence 

 of preservatives like salt, formalin, etc., is likely to increase loss 

 of fat. Jarring or stirring the milk after coagulation has com- 

 menced and before it is completed results in increased loss of fat. 

 Other conditions causing abnormal losses of fat are cutting the 

 curd when it is too soft or cutting it too fine; violent, careless and 

 rapid motions of knife m cutting curd; heating curd too rapidly 

 or too high; piling curd too much; putting curd to press too warm; 

 too rapid application of pressure in cheese hoop. Fermentations 

 producing floating curd, excessive acidity of milk and forms of fer- 

 mentation that dissolve casein also contribute to losses of fat in 

 cheese-making. 



(3.) Loss of Milk-Casein in Cheese-Making. — The casein lost in 

 cheese-making is probably lost mostly in the form of fine particles of 

 coagulated paracasein, which pass through the strainer when the 

 whey is removed from the curd. These minute particles can readily 

 be seen by letting a pail of freshly-drawn whey stand until the curd 

 particles settle, and then pouring off the whey, when a noticeable 

 quantity of finely-divided curd can be seen at the 'bottom of the pail. 

 This passage of curd into whey is not entirely avoidable, but is 

 made needlessly greater by careless or violence io cutting curd 

 and in subsequent handling, by agitation while drawing off the whey 

 and by imperfect strainers. Any condition that interferes with 

 the complete coagulation of milk-casein by rennet causes loss of 

 casein. Some forms of fermentation convert the casein into com- 

 pounds not acted on hj rennet or dissolve the curd after coagula- 

 tion, and thus cause a loss of 0.1-0 to 0.15 pound of casein, and this 

 loss appears to be quite independent of the amount of casein in 

 the milk. 



G8. Relation of Composition of Milk to Composition of Cheese. 



It was formerly believed that cheese of the same composition is 

 made from all kinds of milk. On this assumption the partial skim- 

 ming of milk for cheese-making was defended. 



(1.) In Normal Milk. — In the following table, we pr(>sent some 

 dgurcs showing how the change in composition of milks affects the 



