(b) METHOD OF THE MASSACHUSETTS BOARD OF HEALTH FOR ANNATO. 



Treat 2 or 8 grams of the melted and filtered fat (freed from salt and water) with 

 warm, dilute sodium hydroxid, and after stirring pour the mixture while warm upon 

 a wet filter, using to advantage a hot funnel. If annato is present, the filter will 

 absorb the color so that when the fat is washed off by a gentle stream of water the 

 paper will be dyed straw color. It is well -to pass the warm alkaline filtrate two or 

 three times through the fat on the filter to insure removal of the color. If, after 

 drying the filter, the color turns pink on application of a drop of stannous chlorid 

 solution the presence of annato is assured. 



(<;) GEISLER'S METHOD FOR AZO COLORS. & 



A few drops of the clarified fat are spread out on a porcelain surface and a pinch 

 of fuller's earth added. In the presence of various azo dyes a pink to violet-red col- 

 oration will be produced in a few minutes. Some varieties of the fuller's earth react 

 much more readily than others with azo colors. 

 dj. Am. Chem. Soc., 1898, 20: 110. 



(d) LOW'S METHOD FOR AZO COLORS. e 



A small amount of the material to be tested is melted in a test tube, an equal vol- 

 ume of a mixture of one part of concentrated sulphuric acid and four parts of glacial 

 acetic acid is added and the tube is heated nearly to the boiling point, the contents 

 being thoroughly mixed by shaking. The tube is then set aside and after the acid 

 solution has settled out it will be found to be colored wine- red in the presence of azo 

 color, while with pure butter fat comparatively no color will be produced. 



ej. Am. Chem. Soc., 20: 889. 



(e) DOOLITTLE'S METHOD FOR AZO DYES AND ANNATO./ 



The melted sample is first filtered. Two test tubes are taken and into each are 

 poured about 2 grams of the filtered fat, which are dissolved in ether. Into one test 

 tube 1 or 2 cc of dilute hydrochloric acid are poured and into the other about the same 

 volume of dilute potassium hydroxid solution. Both tubes are well shaken and 

 allowed to stand. In the presence of azo dye the test tube to which the acid has been 

 added will show a pink to wine-red coloration while the potash solution in the other 

 tube will show no color. If annato has been used, on the other hand, the potash 

 solution will be colored yellow, while no color will be apparent in the acid solution. 

 /Qualitative tests of the curd should be made; see J. Am. Chem. Soc., 1902, 22: 150. 



Also on page 39 strike out section U 9. Detection of Anilin Colors," 

 and insert the following: 



9. DETECTION OF BORIC ACID IN BUTTER. 



Melt about 25 grams of the sample on .the water-bath, pour off the fat from the 

 aqueous solution that settles to the bottom of the container, acidify the aqueous^solu- 

 tion slightly with hydrochloric acid, and test in the usual manner with turmeric paper 

 for boric acid. 



On page 40, under "5. Determination of Fat," insert the heading 

 " (a) Official method e " for the method there given, and on page 41, at 



the close of this method, insert the following as a provisional method: 



/ 



(b) LYTHGOE'S MODIFICATION OF THE BABCOCK METHOD. c 



c Farrington and Woll, Testing Milk and Its Products, 1st ed., p. 78. 



Weigh accurately about 6 grams of the sample in a tared beaker. Add 10 cc of 

 boiling water and stir with a rod till the cheese softens and an even emulsion is 



