BUREAU OF CHEMISTRY. 223 



to develop mctliocls for the detection of spoilage in cream and butter. 

 The flora of the A'arious types of old cream, the products of the action 

 of microorganisms that may be present in such cream, the effect of 

 neutralizing and pasteurizing it before churning, the production of 

 butter from it, and the possible occurrence of the products of the meta- 

 bolism of microorganisms in the butter are being studied. This in- 

 vestigation is conducted mainly in the field, in cooperation with the 

 creameries. As such work can be done in a satisfactory manner only 

 during a portion of the year, it is probable that it will be necessary to 

 continue it through several seasons. 



BEVERAGES. 



An article entitled "Composition and Food Value of Bottled 

 Soft Drinks" was published m the Department Yearbook for 1918. 



Tlie work begim last year upon the substitution of other sweeten- 

 ing agents for sugar as a means of sugar conservation was continued. 

 Three articles on the subject, published in the trade journals dur- 

 ing 1918, were widely copied. Three other articles were added this 

 year, " Refiners' Sirup for Bottlers," " Soft Drinks without Sugar," 

 and '' Substitute Sirui>s for Soft Drinks." With the cooperation of 

 the United States Food Administration, many thousands of copies of 

 a brief resume of the subject were distributed, and the information 

 given in person at meetings of the trade. A valuable service was thus 

 rendered the soft-drink industry, and many bottlers who were un- 

 able to secure sugar were saved from disaster. Some of the substi- 

 tutes proved to have such merit that they probably will remain in 

 permanent use. 



Studies have been conducted upon soda flavors and upon the flora 

 of sweetened nonalcoholic beverages. An article has been prepared 

 upon the longevity of bacteria in commercial bottled water. 



CITRUS BY-PRODUCTS. 



The citrus by-product project was organized on its present basis 

 in 1014, the object being to develop first upon a laboratory, and 

 later upon a commercial scale methods for the manufacture of sal- 

 able products from citrus fruit not suitable for shipment as fresh 

 fruit. Minor defects, such as small bruises or punctures from 

 thorns, gravel, or rough boxes, destroy the shipping value of fruit, 

 as such defects offer points for infection to various bacterial and 

 fungous growths which cause decay. Fruit that is too small or too 

 large, unsightly or misshapen, has also a doubtful shipping value. 

 The amount of waste fruit averages from year to year about 3 per 

 cent of the total crop. 



The by-product laboratory at Los Angeles has been studying the 

 utilization of cull oranges in making stable products. Marmalade, 

 marmalade stock, juice, vinegar, and candied peel are possibilities 

 in this direction. Methods for the production of all of these, except 

 juice, have been developed, and either have been given to the public 

 or are now ready for publication. Candied peel and juice of excel- 

 lent quality can be made from grapefruit, and methods for their 

 production have been devised and given to the industry. 



The existing methods for the manufacture of citrate of lime and 

 citric acid have been improved and adapted to California conditions. 



