APPENDIX 317 



deducted from the nitrogen obtained as described. (Farrington 

 and Woll, Testing Milk and Its Products, p. 221.) 



82. Coloring Matter and Preservatives. All certified milks 

 and creams shall be free from adulteration, and coloring matter 

 and preservatives shall not be added thereto. 



83. Tests for the detection of added coloring matter shall be 

 applied whenever the color of the milk or cream is such as to 

 arouse suspicion. 



Test for Coloring Matter. The presence of foreign color- 

 ing matter in milk is easily shown by shaking 10 c.c. of the milk 

 with an equal quantity of ether ; on standing, a clear ether solu- 

 tion will rise to the surface ; if artificial coloring matter has been 

 added to the milk, the solution will be yellow colored, the inten- 

 sity of the color indicating the quantity added; natural fresh 

 milk will give a colorless ether solution. (Testing Milk and Its 

 Products, Farrington and Woll, p. 244.) 



84. Tests for the detection of formaldehyde, borax, and 

 boracic acid shall be applied at least once each month. Occa- 

 sionally application of tests for the detection of salicylic acid, 

 benzoic acid, and the benzoates are also recommended. (See 

 pages 257 to 260.) 



85. Detection of Heated Milk. Certified milk or cream 

 shall not be subjected to heat unless specially directed by the 

 commission to meet emergencies. 



86. Tests to determine whether such milks and creams have 

 been subjected to heat shall be applied at least once each month. 

 (See page 298.) 



87. Specific Gravity. The specific gravity of certified milk 

 shall range from 1.029 to 1.034. 



88. The specific gravity shall be determined at least each 

 month. (See page 228.) 



METHODS AND REGULATIONS FOR THE MEDICAL EXAMINA- 

 TION OF EMPLOYEES, THEIR HEALTH AND 

 PERSONAL HYGIENE 



89. A medical officer known as the attending dairy physi- 

 cian shall be elected by the commission, who should reside near 

 the dairy producing certified milk. He shall be a physician 

 in good standing and authorized by law to practice medicine; 



