192 ADULTERATION OF MILK. 



The effect of the added water is. to lower the specific' gravity 

 and also the percentage of all the ingredients. 



The determination of fat alone is not sufficient to indicate 

 in all cases whether or not water has been added to milk. 

 This could be illustrated by many instances, notably in the 

 case of Jersey milk containing 6% fat. Such milk could be 

 diluted with 50% water and at the same time yield 4% fat. 

 Judged by the fat content alone, the watered milk would be 

 considered of high quality, while the nutritive value would be 

 only two-thirds of the normal. Serious mistakes have been 

 made by modifying for infant feeding just such watered milk, 

 upon the assumption that it was a normal milk containing 4% 

 fat. 



The determination of the specific gravity when the only 

 sophistication of the milk is that of added water, is of great 

 value. A low specific gravity, that is, below 1.028, with a low 

 fat content, is a very sure indication of added water. When 

 an inspector finds such conditions the sample should be exam- 

 ined by the immersion refractonieter. Full directions for 

 using this instrument are' to be found in Leach (5). A read- 

 ing below 39 indicates added water, between 39 and 40 the 

 sample is to be regarded as suspicious. If it is not possible to 

 have access to a refractonieter a determination of milk sugar 

 will be very helpful. A low sugar content, that is, below 

 4%, in connection with a low gravity and fat, indicates added 

 water. 



Skimming:. The removal of the cream is to be considered 

 an adulteration in that the consumer is deceived and misled. 

 Evidence regarding whether or not a given sample of milk has 

 been skimmed is mainly gathered from results of the test for 

 fat. The only cases where this test is not reliable are to be 

 found in the rich milks of the Channel Island breeds, which 

 can be skimmed and still indicate a fat per cent, above many 

 of the legal standards. 



Carbonate of soda. This and the bicarbonate are occasion- 

 ally used to lessen the acidity of old milk. The addition of 

 these compounds to milk is to be considered in that they are 

 added to conceal inferiority. For detection, see Leach (5). 



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