118 EVApPoratED Mi,K—HEATING 
casein to curdle, tends toward the formation of a hard, unshak- 
able coagulum during sterilization, and makes the manufacture 
of a marketable product difficult. Abnormal milk of this type 
may come from cows approaching parturition, or too soon after 
calving, or milk from cows suffering from disease, generalized 
or loeal, or from cows in poor and abnormal physical condition 
which may be brought about by poor care. over-feeding, feeding 
the wrong kinds of feed, or feed in poor condition, exposure to 
abnormally hot weather and flies, or any other condition which 
disturbs the physiological functions of the animal and thereby 
affects the physical, chemical, and physiological properties of 
the milk; or it may be due to improper care of the milk, causing 
it to be excessively contaminated with germ life, or to be rel- 
atively high in acid. All such milk renders the quality of the 
finished product uncertain and mav result in heavy loss. 
In view of these facts it is obvious that the greatest care 
should be exercised on the receiving platform, inspecting every 
can of milk, using the most reliable means, as recommended in 
Chapter I1] on “Control of Quality,” to detect suspicious milk, 
and rejecting all milk that fails to reach the sanitary standard 
adopted by the factory. 
Standardizing.—In order to insure in the finished product 
the percentage relation of fat to solids not fat that meets with 
the Federal Standard or with any other standard desired, the 
fluid milk should be accurately standardized. For this purpose 
each batch of fluid milk must be correctly tested for per cent fat 
and per cent solids not fat. On the basis of these tests, the 
amount of cream or skim milk which it is necessary to remove 
or to add, as the case may be, can then be readily calculated. 
For detailed directions on standardizing the milk to any desired 
standard see Chapter XXIX on “Standardization.”’ 
HEATING THE MILK. 
The equipment for heating the milk should be such as to 
enable the factory to heat the milk with the least possible delay 
so as to avoid the development of acid, or to make possible the 
prompt cooling of the milk upon its arrival to a temperature at 
which bacterial development is checked. In the manufacture of 
evaporated milk, the batches of condensed milk in the vacuum 
