32 



Condensed Milk and Milk Powder 



as milk containing colostrum, etc., or the proteids of which are un- 

 stable for other reasons. 



Making the Test. — The boiling test is simple and can be ma- 

 nipulated rapidly. A sample of the questionable milk is taken into 

 a small dipper. The dipper is held up against a steam jet turned 

 down into the milk. Direct steam is turned into the milk until it 

 comes to a boil. If flakes or specks of curd cling to the sides of the 

 dipper, the milk is unfit for use. 



An alcohol lamp or gas burner on the 

 platform may be used for heating the sam- 

 ple. In this case a few cubic centimeters of 

 the milk are discharged with an ordinary 

 pipette into an ordinary test tube, such as 

 are in common use in the chemical labora- 

 tory and can be obtained from the drug 

 store. The tube is held over the flame and 

 the milk comes to a boil in less than a min- 

 ute. If the milk is in good condition the 

 sides of the glass tube remain perfectly clear. 

 If it curdles upon heating, the sides of the 

 tube show fine specks of curd. The appear- 

 ance of these specks condemns the milk. 



The Sediment Test. — This test shows 

 the relative amount of dirt present in milk. 

 One half pint of milk is passed through a 

 small circle of absorbent cotton and the 

 amount of mechanical impurities present in the milk is indicated by 

 the color of the cotton after filtration. In order to hasten the 

 filtration, the milk is forced through the filter under slight pressure. 

 This is accomplished by a rubber bulb attachment to the apparatus, 

 as shown in the accompanying figure. 



If the cotton retains a white or creamy color, the milk is rela- 

 tively free from filth. Milk produced under unsanitary conditions 

 stains the cotton brown or black. 



These cotton filters may be pasted on a sheet of paper similar 

 to a milk sheet, arranged so that the circles are placed opposite the 

 respective patron's name or number. When shown to the patrons 

 who come to the factory, they furnish a most effective object lesson 

 to them. When the milk reaches the factory on route wagons or 



Fig. 5. 

 The sediment tester 



