BUREAU OF CHEMISTRY. 277 



re^ardinor processes of manufacture, stud}' the composition of foods 

 and of materials that enter into the manufacture of food, review evi- 

 dence in cases, furnish expert testimony, and in fjeneral develop in- 

 formation to aid the administrative offices of the bureau in arriving 

 at decisions and in formulating policies and to aid the field offices in 

 carrying; out their re^rulatory projects. 



The following investigations by certain of the staff laboratories 

 indicate some of the more important problems under consideration 

 and illustrate the variety and extent of the work. 



FOOD-CONTROL INVESTIGATIONS. 



The food-control laboratory, which, as its name indicates, super- 

 vises the chemical work on foods, also conducts investigations neces- 

 sary for effective food control not provided for in other staff labora- 

 tories. The hydrogen-ion concentration of egg whites is being 

 studied with the view of determining its effect on the whipping 

 qualities of the different egg-white preparations. Methods of analy- 

 sis have been worked out in preparation for a study of the composi- 

 tion of alimentary pastes and the raAv materials used in their manu- 

 facture. In connection with the investigation of alimentary pastes, 

 samples of whole eggs, egg yolks, and egg albumen in tlie dried con- 

 dition were collected and anatyzed in order to assist in determining 

 the nature of the egg material used in egg noodles. A method for 

 detecting remade milk has been published. All available data on 

 flour grades and flour standards were assembled and submitted to 

 the joint committee on definitions and standards for consideration 

 in formulating standards. Experimental batches of^ prepared mus- 

 tard have been analyzed in a study of mustard products with the 

 view of preparing recommendations for the labeling of mustard 

 products containing hulls and turmeric. Numerous analyses of au- 

 thentic samples of cocoa nibs were made and the data submitted to 

 the joint committee on definitions and standards for a revision of 

 the cocoa and chocolate standards. 



MICROBIOLOGICAL INVESTIGATIONS. 



The microbiological laboratory investigates food problems in 

 which bacteria and other microorganisms are iuA'olved. This in- 

 cludes the examination of samples taken under the food and drugs 

 act to detect adulteration, contamination, and pollution. The labora- 

 tory controls the microbiological examination of foods and drugs in 

 the three field districts of the bureau. During the year special 

 attention was given to the examination of water for pollution, sal- 

 mon for spoilage, and canned foods, particularly spinach, for Bacil- 

 his hotulinus. 



A boric-acid canning powder was investigated to determine its 

 value and fitness for use in canning. In the practical canning ex- 

 periments the use of the powder for acid products was shown to be 

 an unnecessary and wasteful practice, since material packed without 

 the powder kept as well as that packed with it. Its use with the more 

 or less neutral vegetables showed that the powder plus the inadequate 

 heating recommended was not sufficient to preserve the materials or 

 to prevent the production of toxin in them by B. totulirms. As the 



