190 One Thousand Questions in Agriculture 



Separator as Milk Purifier. 



/ have a neighbor who contends that a cream separator purifies the 

 milk that passes through it. I say that it does not purify the milk. I 

 agree that it does take out some of the heavy particles of dirt and Alth, 

 but that it cannot take out what is already in solution with the milk. 



The purification naturally cannot be very great, and if milk is 

 produced in unsanitary fashion, running through the separator will 

 do little, if any, good. Nevertheless, the separator does remove more 

 than just the solid particles of dirt. The purifying comes by leaving 

 behind the separator slime, so called, the slimy material left behind 

 after a good deal of milk has been run through. In fact, some 

 creameries separate milk, only to mix milk and cream again, largely 

 for the purpose of removing the impurities found in the slime. In 

 this slime are not only the impurities that fall into the milk, but also 

 some of the fibrous matter that is part of the milk, and this gathers, 

 being pulled out by gravity as are the fat particles, it seems to 

 gather with it a few more bacteria than remain in the milk itself. 

 Material in real solution, as sugar is in solution in water, naturally is 

 practically unaffected by separation. You are, therefore, right to the 

 extent that you cannot produce unsanitary milk and clean it with the 

 separator, but your neighbor is right to the extent that the separator 

 does remove some impurities and is used just for that purpose. There 

 is also in the dairy trade a centrifugal milk clarifier which is con- 

 structed in somewhat similar manner to a cream separator, but acts 

 dififerently on the milk in not interfering with cream rising by gravity 

 when separated cream and milk are mixed after cleaning. 



Butter Going White. 



/ bought some butter and during the zvarm iveather it melted. About 

 40 or 50 per cent was zvhite, zvhile the balance was yellow and went to 

 the top. When the butter remelted, the yellow portion melted, leaving the 

 zvhite portion retaining its shape. The zvhite portion did not taste like 

 ordinary butter. The butter made from our cozvs' cream melted at a 

 higher temperature, but did not have a zvhite portion. Why did our 

 butter not act like the creamery butter? 



Samples of butter have occasionally been sent to this office that 

 have turned white on the outside, and since the white part has a very 

 disagreeable, tallowy flavor, people think that tallow or oleomargine 

 has been mixed with it, but we have never been able to find any 

 foreign substance in any of the samples. We have found that some 

 of the best brands of butter will turn white first on the outside and 

 the white color will gradually go deeper if the butter is exposed to 

 a current of air or if left in the sun a short time. — F. W. Andreason, 

 State Dairy Bureau. 



What Is "Butter-fat?" 



/ would like to know what "butter-fat" means. I have asked farmers 

 this question and no one seems to knozv. I suppose all parties dealing 



