CHAPTER VIII. 



COMPOSITE SAMPLES. 



Definition. In order to avoid testing each patron's milk 

 or cream every day for fat, a small sample, which represents 

 the average quality and a proportionate part of the whole, is 

 taken from each patron's milk every day and placed in a jar. 

 A preservative of some kind is previously added, which keeps 

 it from spoiling. This is called a composite sample. 



When to Sample. Some makers prefer to sample the milk 

 or cream delivered every day; others prefer to sample every 

 other day. Some creamery operators, again, sample four or 

 five times in succession at intervals, the patrons being unaware 

 of the time when the sampling is to take place. The most 

 reliable and practical method, however, is to take a sample 

 every day, and test it for fat at the end of every two weeks. 

 When cream is received it is not reliable to take composite 

 samples. 



Kind of Preservative to Add. A number of different pre- 

 servatives are now in use, and different ones are being recom- 

 mended for creameries and cheese factories by various authori- 

 ties. Even a few of the best authorities differ as to which 

 one of the preservatives gives the best results. 



Among the most common of the milk preservatives, and 

 less poisonous than certain others, are salicylic acid, borax, 

 boracic acid, and bicarbonate of soda. Among the more vio- 

 lent poisons and strong preservatives are formaldehyde and 

 its compounds, chloroform, corrosive sublimate, and bichromate 

 of potash. Bichromate of potash and corrosive sublimate are 

 the two most commonly used in preserving composite samples. 

 The former is recommended highly by Farrington & Woll on 



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