84 MODERN METHODS OF TESTING MILK 



sample is being taken and cream is added to the jar 

 until it rises to the mark representing the number of 

 pounds of cream delivered. 



Amount of sample. It is a safe precaution to take 

 a sample sufficient to make at least two tests ; from i 

 to 1^2 ounces (30 to 45 cc.) will answer the purpose 

 when each delivery is tested; less from each delivery 

 will answer in case of composite sample. 



METHOD OF KEEPING CREAM SAMPLES 

 In general, the same precautions are observed in 

 keeping samples of cream as in the case of milk (p. 

 20), whether single or composite samples. Samples 

 that are not tested soon after reaching the creamery 

 should be treated with a small amount of preservative 

 (p. 28). With thick cream, special effort should be 

 made to cause the preservative, especially bichromate, 

 to dissolve completely and be distributed through the 

 sample. This may be done by agitating the cream 

 carefully by a gentle, rotary motion, warming slightly 

 if necessary. With composite samples, the contents of 

 the bottle are shaken after each addition of cream until 

 there is a complete, uniform mixture. It may be said, 

 in general, that lack of proper care of cream samples 

 introduces even greater errors in the results of the test 

 than is the case with samples of milk. 



AGE OF SAMPLES WHEN TESTED 

 In the best-managed creameries, cream is delivered 

 two to three times a week and each individual ship- 

 ment is sampled and tested on the day of delivery or 

 within 24 hours. The method of using only com- 

 posite samples in cream-testing is gradually being 



