BUREAU OF CHEMISTRY. 557 



The studies reo;arding tomato spoilage have been extended in col- 

 laboration with the branch laboratories and additional data secured 

 which is of value in the interpretation of the results obtained in the 

 examination of tomato ketchup. Analysis was made of many of the 

 common brands of ketchup sold on the American market. As would 

 be expected, the decomposition of tomatoes in various localities does 

 Jiot proceed uniformly because of the lack of uniformity in the organ- 

 isms which have led to the decomposition. The work has been ex- 

 tended, therefore, in collaboration with the microchemical and bac- 

 teriological laboratories by the application of pure cultures isolated 

 from spoiling tomatoes in varying localities. This work was begun 

 in April, since Avhich time 16 samples subjected to the action of defi- 

 nite organisms have been examined from time to time. 



The same general methods have been applied to the study of the 

 common berries on the market, but have not been found to be so gen- 

 erally applicable. 



Some attention has also been given to methods for the detection of 

 spoilage in other products, as frozen and desiccated eggs, gelatin, 

 and coffee containing a large number of imperfect or decayed berries, 

 ordinarily known as quakers and black jacks, and also of coffee 

 that has been damaged by various causes during shipment. 



Fruit Products. 



Economic studies. — The studies on fruits and fruit products in 

 collaboration with pomologists in charge of the field investigations 

 of the Bureau of Plant Industry have been continued. A field study 

 on the processing of Japanese persimmons to render them nonastrin- 

 gent was made during the past season and the results published. It 

 was found that all varieties of Japanese persimmons tried could be 

 satisfactorily jn'ocessed on the large scale by keeping them in carbon 

 dioxid for a time varying with the variety and the temperature. 



The methods previously applied to the preparation of grape juice 

 and apple juice have been studied with reference to the modifica- 

 tions necessary for their application to juices of other fruits, and the 

 juice-yielding properties of many varieties of grapes grown in the 

 eastern part of the United States have been studied in collaboration 

 with the viticulturist of the Bureau of Plant Industry. A study 

 has also been made of methods for the preparation and preservation 

 of orange and lemon juices to make them hold their color and flavor. 

 In the last year it has been found possible to prepare juices which 

 hold their color for several months and whose flavor deteriorates 

 much less than in juicas heretofore prepared. Recent studies indi- 

 cate the possible value of concentration of such juices by means of 

 freezing. This method appears promising, from the experimental 

 study that has been made, and it is proposed later to conduct a small 

 commercial experiment to determine its cost. 



A study on a small laboratory scale has been made of the drying 

 of fruits in vacuum, together with an absorbent for water vapor, such 

 as unslaked lime. The quality of the article prepared in this man- 

 ner is so satisfactory as to make it appear advisable to conduct ex- 

 periments on a small manufacturing scale for the purpose of deter- 

 mining the cost, and also in order that a sufHcient amount of the 

 product may be prepared for a study of its maintenance of color and 

 flavor during storage. 



