52 DAIRYING 



after each skimming, and two-thirds to one-half are not washed 

 until after using two or three times for skimming milk. 



This attempt to save work and to put off the cleaning as long 

 as possible has an injurious effect on the quality of the cream or 

 butter made from the cream, because the slime and dirt left in the 

 separator bowl after the first skimming decomposes very fast and 

 taints the next lot of fresh, sweet milk run through it. This is 

 one of the important causes of the inferior quality of farm sepa- 

 rated butter, about which so much has been said in recent years. 



A dirty separator is not only the cause of a loss to the user 

 of such a machine because it taints the cream from sweet milk, 

 but the dirty separator does not skim so well as a clean one; the 

 slime left in the dirty bowl may clog the small skim milk and 

 cream tubes in the bowl and thus prevent the free passage of milk 

 through them while the separator is skimming. 



315. A report made by Hunziker on this point showed that 

 at 35 dairies where the separator bowl was taken apart and thor- 

 oughly cleaned each time it was used, the highest test of the skim 

 milk was .12%, the lowest .02%, and the average .038%, while at 

 23 dairies where the separator bowl was cleaned only once a day 

 the skim milk tests ranged from .72% to .02% with an average of 

 .1% fat, making an average difference of .06% fat in the skim milk 

 from the clean and dirty separators or from washing it once or 

 twice a day. If the skim milk from a dirty separator tests as 

 high as it did in one case, .72% fat, this means a loss from using 

 a separator without washing each time after skimming of 35 

 pounds fat in the skim milk of a cow giving about 6,000 pounds 

 of milk in a year, or 40 pounds of butter at 25 cents per pound 

 amounts to $10, and the same loss in a herd of 10 cows amounts 

 to $100 per year, which added to the cost of a new machine that 

 in many cases is $100, makes the hand separator an expense, of 

 $200 per year to the dairy that fails to wash the separator each 

 time it is used, and on this account leaves .72% fat in the skim 

 milk. 



If this is added to the losses caused by taints introduced into 

 the cream from a dirty separator, the total losses amount to high 

 pay for the time required to carefully clean a separator bowl and 

 all its parts after each skimming. 



