26 EXPERIMENTS ON THE SPOILAGE OF TOMATO KETCHUP. 



paste, was mixed with two-thirds its volume of alcohol. To 10 cc of 

 tomato bouillon were added 0.1, 0.2, 0.3, 0.4, and 0.5 cc, respectively, 

 of the oils of cinnamon, cloves, mace, mustard, and black pepper. 



In the case of the mold, there was no development in the solutions 

 containing cinnamon, cloves, and mustard; in those containing mace 

 and black pepper the development was slower than the normal, that 

 in the black pepper being more pronounced. On the yeast the effect 

 was similar, no development occurring in the cinnamon, cloves, and 

 mustard, and a retarded development taking place in the mace and 

 black pepper, that in the black pepper being the more pronounced. 



The experiments show that some of the spices, notably allspice, 

 cinnamon, and cloves have decided antiseptic value, but that the 

 peppers are not as valuable as is generally supposed. 



The oil extracts have been advocated for use in ketchup instead of 

 the whole spices, but in quantities which would be useful antiseptic- 

 ally their use would be objectionable, for when present in approx- 

 imately the same proportions as are the whole-spice infusions, the 

 flavor is too strong and masks the more delicate flavor of the tomato. 

 The acetic-acid extracts are more effective than are the water infu- 

 sions, and they are not objectionable in the ketchup. 



VINEGAR AND ACETIC ACID. 



An experiment was made to determine the antiseptic value of 

 vinegar and acetic acid. Commercial 50-grain distilled vinegar 

 was used. It was found that when 30 per cent of this vinegar was 

 added to the tomato bouillon the development of mold was checked 

 and the extent to which it was checked increased with the increased 

 amounts of vinegar. The development in the solution containing 30 

 per cent of the vinegar was two days later than the normal in 

 starting, while the solution containing 100 per cent was eleven 

 days delayed and showed but little growth. 



An 80 per cent solution of glacial acetic acid was used. One-half 

 of 1 per cent added to the tomato bouillon checked growth to the 

 same extent as. 30 per cent of vinegar, and no development occurred 

 when the quantity was increased to 2 per cent. 



Experiments were then made in which vinegar was added to 

 the ketchup in proportions varying from 1 part in 32 to 1 part in 

 8, with the result of greatly delaying the appearance of the mold 

 as the proportion increased. With the increase in vinegar it was 

 necessary to add sugar and slightly more spices to overcome 

 the pungency of the acid and thus insure good flavor. The addi- 

 tion of the vinegar to the pulp had the effect of arresting the 

 action of the oxidase and thus the bright color was maintained. 



The usual custom in factory practice is to add the vinegar near 

 the close of the cooking process otherwise a considerable portion 



