124 Testing Milk and Its Products. 



147. Detecting boracic-acid preservatives in milk. The applica- 

 tion of the alkaline tablet test for detecting boracic acid in milk 

 was first discussed in bulletin No. 52 of Wisconsin experiment 

 station. The acidity of the milk is increased by the addition 

 of boracic acid, but neither the odor nor the taste of the milk is 

 affected thereby. By adding to sweet milk the amount of boracic 

 acid which will keep it sweet for 36 hours, its acidity may be 

 increased to .35 per cent., in a sample of milk which previously 

 tested perhaps only .15 per cent. acid. 



As before stated, unadulterated milk will usually smell or 

 taste sour or "turned," when it contains .30-.35 per cent, acid 

 (118); milk testing as high as this limit, which neither smells 

 nor tastes sour in any way, is therefore in all probability adul- 

 terated with some preparation containing boracic acid or a 

 similar compound. 



148. "Alkaline tabs." These are not alkaline tablets, but a sub- 

 stitute which was put on the market by a New York firm. 

 The outfit furnished consisted of four packages of paper discs 

 made of filter paper, each of about the size of an old-style copper 

 cent; two packages of square paper; one glass of about 10 cc. 

 capacity, and one small glass bottle. An investigation of the 

 reliability of these "Tabs" soon disclosed the fact that they 

 were entirely inaccurate, and that no dependence could there- 

 fore be put on the results obtained by their use. 



