180 Testing Milk and Its Products. 



to this may be found in separating rich milk having 

 large fat globules or milk from fresh milkers, in either 

 of which cases the large size of the fat globules occasions 

 a more complete separation of fat by the centrifugal 

 force. But generally speaking, the statement holds good 

 that the total loss of fat in separator skim milk is a factor 

 of the quantity of milk run through the separator, rather 

 than of its quality. It follows from this, however, that 

 the relative losses of fat in skim milk will vary to some 

 extent according to the quality of the milk separated. 

 Selecting two extremes in the quality of milk, 2.5 and 

 6.0 per cent, of fat, there will be found, say .2 per cent, 

 of fat in the skim milk from either lot, provided the sep- 

 arator is not unduly crowded, and the separation is con- 

 ducted under normal conditions in each case. But .2 

 per cent, fat makes 8 per cent, of the total fat in the poor 



(2x100 \ 

 2 5 = ^)> an( ^ on ^ ^ P er cem ^ f t na t i* 1 the 



rich milk. It takes 4000 Ibs. of the 2.5 per cent, milk 

 to furnish 100 Ibs. of fat, and only 1666 Ibs. of the 6 per 

 cent, milk; in skimming the poor milk, a loss of .2 per 

 cent, of fat is sustained in the skim milk from 4000 Ibs. 

 of milk, while in the rich milk a similar loss is sustained 

 in the skim milk from only 1666 Ibs. of milk. 



The example gives an extreme case, and one not likely 

 to be met with in practice. The range in the richness of 

 the milk delivered by different patrons at the factory is 

 usually within one-half or one per cent, of fat. In such 

 cases the proportion of fat lost in skimming does not vary 

 much, e.g., in case of milk containing 3.5 and 4.0 per 

 cent, of fat, and variations in the overrun occurring when 

 the proper care in skimming, ripening and churning is 



