Condensed Milk and Milk Powder 223 



of the control, it is advisable to take composite samples. Use pint 

 jars with tight lids ; label the jars with the number of the respective 

 patron and place them in numerical order on conveniently located 

 shelves on the receiving platform. In the case of the route system 

 of receiving milk, the samples of milk from each route should be 

 stored together. Use a dipper holding one ounce of milk ; by pour- 

 ing a dipperful of milk of each patron each day into the respective 

 jars, enough milk is collected in each jar at the end of two weeks 

 to test with the lactometer arid the Babcock test every two weeks. 



In order to preserve the samples in proper condition drop a 

 large corrosive sublimate tablet into each empty jar and after each 

 addition of milk, mix the corrosive sublimate with the milk by giv- 

 ing the jar a rotary motion. Add one dipperful of each patron's 

 milk daily into the jars. 



Testing the Composite Samples. — At the end of every two 

 weeks test the samples with the Quevenne lactometer and the Bab- 

 cock test. The samples should have a temperature of 55 to 65 de- 

 grees F: In summer and at any other time when the temperature 

 naturally is much higher or lower, place the sample jars into a tank 

 or tub of water at the desired temperature, from one half hour to 

 an hour before testing. For directions for the use of the lactom- 

 eter and the Babcock tester, see Chapter XXX, "Milk," page 200. 

 If the milk contains corrosive sublimate, deduct one-half point from 

 the lactometer reading for each tablet in one pint of sample. 



Interpretation oe Results. — The lactometer reading and the 

 per cent, fat alone furnish a pretty safe index to the freedom from, 

 or presence of adulteration of the milk. From these two factors 

 other guides, such as the specific gravity, per cent, of total solids 

 and per cent, of solids not fat of milk, and specific gravity of the 

 milk solids may be calculated. These are of additional assistance to 

 the inspector. All of these factors vary considerably with the indi- 

 viduality, breed', -period of lactation and feed of the cows, so that 

 considerable latitude must be allowed in determining whether or not 

 any given sample of milk 'has been adulterated. These variations are 

 greatest between individual cows and between different breeds, but 

 they also are quite striking in milk of the same cows from day to day 

 and at different stages of the period of lactation. In mixed herd 

 milk, such as the condensery largely receives, the composition is 



