122 MANUAL OF MILK PRODUCTS 



can several times and the entire contents of the can must be 

 thoroughly agitated. Thick cream should be warmed until it 

 pours readily; frozen cream should be warmed until the icy 

 portions have completely disappeared. Churned cream can- 

 not be sampled accurately. Its fat-content may be calculated 

 by testing the buttermilk and estimating the amount of butter. 

 Composite samples of cream. 



Composite samples of cream are not permissible. They are 

 exceedingly difficult to obtain and are prone to give misleading 

 results. 



Care of the cream sample 



The cream samples are in the best condition for testing im- 

 mediately after sampling or as soon as they arrive at the fac- 

 tory. Samples which are not tested upon arrival at the 

 creamery or soon after should be placed in the refrigerator 

 until ready for the tester. The cream sample bottles or tubes 

 should be sealed tightly ; screw top seals or cork stoppers an- 

 swer the purpose. 



Preparation of the cream sample for the test 



Samples of fresh cream of normal richness, and which is not 

 perceptibly separated, can be tested accurately without special 

 preparation, other than mixing thoroughly by shaking or pour- 

 ing before use. Thick and semi-solid samples which are other- 

 wise in good condition should be warmed to about 90 degrees 

 F., then poured gently and weighed at once. Cream samples 

 in which the butter-fat is completely separated and churned, 

 or has formed a compact, tough, and leathery layer, as is the 

 case with old samples not stored at a low temperature, should 

 be heated high enough to melt the butter-fat, 110 degrees F. 

 or above, then shaken thoroughly and weighed out at once. 

 It should be understood that samples in this condition are at 



