HISTOLOGICAL STRUCTURE OF KETCHUP. 33 



account for this. The conidia on the sides of flasks Nos. 9 and 10 

 must have been destroyed, as no ^development took place in either 

 case except in the center of the surface. 



The dry conidia were destroyed at 100 C. when heated for thirty- 

 five minutes; they did not reach a normal development in any case, 

 dven when heated for only ten minutes, many of the conidia being 

 destroyed by this treatment. Where development failed to take 

 place, the conidia were stained with a water solution of eosin, so as 

 to be sure that the effect was death, and not an arrested development. 



The results of the tests do not agree with those obtained in factory 

 practice, where the ketchup is cooked at 100 C. for at least forty 

 minutes and sometimes for fifty or fifty-five minutes, depending on 

 the consistency of the pulp. 



HISTOLOGICAL STRUCTURE OF KETCHUP. 



In ketchup are found parts of all the various tissues of the tomato 

 broken into fine pieces by the action of the cyclone. Although the 

 sieves take out the seeds, skins, and any large pieces, particles of the 

 various tissues are present in size sufficient for identification. Among 

 the distinctive features are the red crystalline bodies in the paren- 

 chyma, which serve to a certain extent to distinguish the paren- 

 chyma from that of other plants which might be used for adultera- 

 tion, and serve also to differentiate the natural from the artificially 

 colored ketchup. Some of the red dye used colors all protoplasm 

 indiscriminately, even that of the fungi present, and as a colored 

 ketchup is usually poor stuff, containing many fungi, the mold 

 filaments, yeast cells, and bacteria receive their share of the color. 

 Other red dye used is in the form of fine powder, which does not go 

 into solution, but is distributed as irregular particles which are dis- 

 tinct from the red crystalline bodies. 



Good ketchup made from whole tomatoes has a clean appear- 

 ance readily distinguishable under the microscope; but the poor 

 ketchup has usually a superabundance of fungi present, fully devel- 

 oped colonies of mold, many forms of conidia, besides yeast-like 

 cells, and different forms of bacteria. All of these may be dead, 

 but neither preservatives nor dosage of odorous spices can disguise 

 their presence. In some of the ketchup examined, which was put 

 up in attractive form and labeled as being made from the whole 

 tomatoes, and which had the appearance and odor of good ketchup, 

 the microscope showed the presence of such quantities of fungi as 

 to leave no doubt that the tomatoes were spoiled when cooked. 

 It is presumable that some of the dealers placing this sort of 

 stuff on the market do not know its condition themselves, and 

 either buy their pulp from other factories or trust its manufacture 



