RECEIVING AND GRADING OF MILK AND CREAM 93 



In the grading of milk or cream, different methods can be 

 used for detecting abnormal milk: (i) through the senses, 

 taste, sight, and smell; (2) by the acid tests; (3) by the fermenta- 

 tion test; (4) by heating; (5) by the Babcock test and the lac- 

 tometer. 



While all of these tests are applicable to the grading of milk, 

 only the first and a portion of the fifth are usually applied to 

 cream. 



i. Detection of Abnormal Milk and Cream through the 

 Senses. In order to detect the different kinds of defective- milk 

 one must be endowed with acute senses of smell, taste, and sight. 

 When the milk is in a good condition, it has a pleasant smell and 

 sweet taste, and appears normal. This applies equally to cream 

 with the exception that not all cream for butter-making is sweet. 

 If milk has a disagreeable smell and taste it cannot produce good 

 butter. As a rule, the quantity of defective milk brought into 

 the average creamery is much in excess of that of really perfect 

 milk. As a consequence it would not be practicable to separate 

 all the defective milk into one class and the perfect into another. 

 The question as to where the line should be drawn between the 

 good, medium, and very bad milk or cream, must depend 

 upon the judgment of the receiver, and in a great measure upon 

 the local conditions. Some of the creameries have no facilities 

 for handling different grades of milk, and some sell butter on a 

 market where no sharp distinction is made between good and 

 poor butter. Others have, through experience, satisfied them- 

 selves that under American creamery conditions it does not pay 

 to make too many grades, nor does it pay to grade too closely. 

 Two, or at the most three, grades of butter can at times be man- 

 ufactured in one creamery profitably. It is advisable to reject 

 sour and abnormal milk. If accepted, it should not be mixed 

 with the remainder of the milk, as it might contaminate all of it; 

 or, the sour milk might cause coagulation, and thereby clog up 

 the separators. If a can of milk is sour, but otherwise clean, it is 

 not necessarily unfit for the production of first-class butter. If 

 retained until after the sweet milk has been skimmed, it may be 

 run through the separator successfully. 



