ADULTERATIONS OF CONDENSED MILK 229 



Causes and Prevention. The metallic flavor may be due 

 to the same cause as metallic sweetened condensed milk, i. e. an 

 unsanitary condition of the vacuum pan, in which case its recur- 

 rence can be readily avoided by thoroughly cleaning all parts of 

 the pan including the dome and the goose neck, and rinsing down 

 the whole pan thoroughly with clean water each morning before 

 operations begin. 



Unsweetened condensed milk made by the use of the "Con- 

 tinuous Concentrator" may have a metallic flavor when the 

 scrapers in this machine are improperly adjusted, causing them 

 to cut into the copper walls and thereby incorporating metallic 

 copper in the product. This source of metallic flavor can be 

 removed by proper adjustment of the revolving spider and its 

 essential parts. 



Evaporated milk may also show a metallic flavor as the result 

 of chemical action of the acid in the milk on the can. This occurs 

 usually only upon prolonged storage. Very old evaporated milk 

 is very prone to have a metallic flavor from this source. It is 

 obvious that this can best be avoided by endeavoring to move 

 the goods sufficiently rapidly to limit the age of the milk to a 

 reasonable period of time. 



Cans, in the manufacture and sealing of which an acid flux 

 is used, are prone to give the contents a puckery, metallic flavor, 

 due to the zinc chloride and hydrochloric acid present. This can 

 be avoided by using cans only in the manufacture of which a 

 non-acid flux, such as gasoline-resin flux, is used, and by using 

 a non-acid flux for sealing the filled cans. 



CHAPTER XXV. 

 ADULTERATIONS OF CONDENSED MILK 



It is the sense of the Federal Pure Food Act that the addition 

 to condensed milk of any substance except sucrose, and the abstrac- 

 tion of any substance from milk except water, is an adulteration. 



Skimming. Condensed milk made from partly or wholly 

 skimmed milk must be labeled and sold as condensed skimmed milk 

 in order to comply with the Pure Food regulations. However, it 

 is possible for condenseries receiving fresh milk, rich in butter fat, 



