IQO/.] METHODS OF JUDGING MILK AND CREAM. 173 



of 4.5 or 5 per cent, does not represent the usual conditions 

 nor necessarily the most desirable composition for general 

 market milk. Others may suggest that the so-called legal 

 standard should be taken as a basis for milk of perfect com- 

 position. It is unfortunate that we use the word standard in 

 connection with the legal requirements governing the compo- 

 sition of milk because, properly speaking, it is not a standard 

 at all but simply a method of prescribing the lowest permissible 

 amounts of fat and solids-not-fat that will be legally tolerated 

 in market milk. 



The number of points that shall be assigned milk of perfect 

 composition, in the sense above given, ofifers much chance for 

 variation of opinion. In my own judgment, it should be given 

 a larger number than any other quality and I would assign a 

 score of 40 points out of 100 for milk containing 4 per cent, 

 of fat and 9 per cent, of solids-not-fat. 



The next question that presents itself is this : What num- 

 ber of points shall we deduct from milk that falls short of the 

 assigned limits? Here again is chance for much variation of 

 opinion. My suggestion is that we. deduct i point for each .1 

 per cent, below 4 per cent, of fat and i point for each .1 per 

 cent, below 9 per cent, solids-not-fat. 



KEEPING QUALITY OF MILK. 



By the keeping quality or power of milk, we mean the 

 length of time milk remains sweet and palatable for direct 

 consumption. In estimating the commercial value of market 

 milk, this is an important factor, since milk that is sour or 

 otherwise unpalatable, or milk that contains the products of 

 any undesirable form of fermentation, is comparatively value- 

 less for direct consumption, however rich it may be in fat and 

 solids-not-fat. Such milk can generally be used in cooking 

 and its full food value utilized. 



The keeping power of milk is dependent upon ( i ) the num- 

 ber and kind of bacteria present and (2) the temperature at 

 which the milk is kept. 



The following factors can be used in gaining knowledge and 

 in measuring the keeping power of milk: (i) acidity, (2) dirt 

 in suspension, (3) fermentation tests and (4) number of 



