MILK AND YIELD OF CHEESE 



191 



Even when cream is added to normal milk to an 

 extent sufficient to raise the fat content to 7 or 8 

 per cent, the increased loss of fat, though consider- 

 able, is not necessarily greater in proportion to the 

 increase of fat in milk. 



AMOUNT OF FAT LOST IN CHEESE-MAKING IN CASE OF 



NORMAL MILKS 



Group 



Number 

 of ex- 

 peri- 

 ments 



Per cent 



of fat 



in milk 



Pounds of fat lost in whey 

 for 100 pounds of milk 



Percent- 

 age of fat 

 in milk 

 lost in 

 whey 



Percent- 

 age of fat 



in milk 

 retained 

 in cheese 



I 



II 

 III 

 IV 

 V 



90.45 

 91.67 

 92.30 

 94.10 

 94.00 



Why it is impossible to prevent loss of fat in 

 cheese-making. — Attention has already been called (p. 

 140) to the fact that fat is present in milk in the 

 form of very small globules, one cubic centimeter 

 of ordinary milk containing between one and two 

 billion globules. When the rennet-extract causes 

 the casein throughout the mass of milk to solidify 

 or coagulate, the fat-globules are retained or im- 

 prisoned in the solidified mass just where they 

 are at the instant of coagulation. When the curd- 

 knife passes through the solid mass, immense num- 

 bers of the fat-globules are exposed on every cut 

 surface and billions of these are disengaged from 

 the free surfaces of the small pieces of curd during 

 its manipulation. The fat-globules, thus detached 



