436 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



Kiyrciiup. — Experiments have been continued by Mr. Bitting in 

 the making of tomato ketchup to increase the time of keeping after 

 opening the container. Tlie Avork showed that Icetchup couhl Ix^ made 

 without any other preservative than sterilization, and such preserva- 

 tive action as may be exerted by the vinegar and suj^ar present, 

 and have it keep as long as it remains sealed, and also for a reason- 

 able time after opening. The ketchup first made had a specific 

 gravity of about LOG, a total acidity of less than 0.9, estimated as 

 acetic acid, and about G per cent of sugar. In the subsequent experi- 

 ments the aim has been to give a heavier body and a higher total 

 acidity in order to offer greater resistance to germs which might find 

 entrance after the bottle has been opened. It was found that ketch- 

 ups having a specific gravitj' of more than 1.12, a total acidity of 

 1.2 per cent or more, estimated as acetic acid, and 12 per cent or 

 more of sugar would keep. All of these figures were greatly ex- 

 ceeded in the experiments, and good ketchup ma}^ be made in which 

 all or only one or two of the factors are increased. It is possible that 

 there may be a decrease in these proportions, though wuth some risk. 

 The greater concentration and the increase in sugar and vinegar 

 have been the chief factors in securing a product of superior keeping 

 properties, cleanliness and sterilization being always essential. 



Examinations were made of commercial ketchups for their specific 

 gravitj', total acidity, condition of the tissues, and the organisms 

 present. A comparison made with the record of a similar examina- 

 tion two years previous show^s a decided improvement in this time. 

 The ketchups were also compared by dividing them into two classes. 

 those preserved with benzoate of soda and those preserved b}'^ steriliza- 

 tion, together with the preservative action exerted by the increased 

 vinegar and sugar present. The latter class has a heavier body and 

 consequently a slightly higher acidity than the former. The ketchups 

 depending mainly upon sterilization and also upon increased vinegar 

 and sugar and concentration for their keeping properties are gener- 

 ally made of higher grade material, and a smaller number of organ- 

 isms are present than in the benzoated products, but there are clean 

 ketchups and dirty ketchups in both classes. 



The condition of the ketchup is determined by the appearance of 

 the cells, whether they are broken or separated by fermentation or 

 decay, and by the number and kind of organisms present and their 

 condition. The general appearance of the ketchujD and its color, 

 taste, and smell may be easily modified by a skilled manufacturer, 

 but no amount of cooking or finishing can change the microscopic 

 structure. 



Fruit and fruit products. — The experimental work on fruit and 

 fruit products has been continued in collaboration with the pomolo- 

 gist in charge of the field investigations of the Bureau of Plant 

 Industry. The fruits studied were grapes, apples, pineapples, 

 peaches, plums, strawberries, raspberries, blackberries, huckleberries, 

 currants, oranges, and lemons. 



Investigations on grape juice were made with the object of study- 

 ing the yields obtained by different methods of pressing and of heat- 

 ing before pressing and the effect of these various procedures on the 

 composition and flavor, working on a scale which could readily be 

 extended to commercial proportions. The studies on juices prepared 



