30 EXPERIMENTS ON THE SPOILAGE OF TOMATO KETCHUP. 



The development of the mold is seemingly dependent on the 

 amount of air in the chamber at the time of sealing. After the air is 

 exhausted, the conidiophores assume fantastic forms, developing only 

 one or a few sterigmata, and on these one or few conidia. In other 

 cases the conidiophores are fascicled, in no cases, however, forming the 

 conidia as luxuriantly as when air is supplied. The hyphae become 

 clear, much vacuolated, and develop more septa, and some of the 

 cells become much enlarged. An enlarged cell will often contain two 

 or three septa, thus forming cells that are not larger than disks. In 

 cultures from which the air was excluded from the start, no develop- 

 ment took place. In test-tube cultures sealed with paraffin after 

 twenty-four hours, the mold developed on the surface of the gelatin, 

 forming a felted white mass, but no conidia nor carpospores were 

 formed. 



GROWTH IN KETCHUP. 



The form of Penicillium which was used in the experiments was 

 isolated from ketchup in which it grew luxuriantly. When conidia 

 are first formed on the ketchup, they are a delicate blue in color ; they 

 then become bluish green, then green, and finally olive. The develop- 

 ment of the color of mold growing on ketchup is practically the same 

 as when grown in wort, tomato bouillon, pea bouillon, or gelatin 

 made with these solutions as a basis. In ketchup containing sodium 

 benzoate, the blue color appearing first remains for a long time, and 

 in old cultures the mold is a dull drab, not olive, as in normal develop- 

 ment. 



In ordinary ketchup made without a preservative, the mold forms 

 a heavy, wrinkled mycelium, showing a large development of conidia. 

 In the bottles of ketchup, the mold pushes down into the ketchup, 

 becoming entirely submerged, a clear liquid covering the mold and 

 separating it from the ketchup. This occurred in more than one hun- 

 dred bottles. No secondary mycelium formed on the surface of the 

 liquid, a method of development which frequently occurs in ordinary 

 media when a mass of mold is submerged. 



An exception to this was shown in ketchup which had developed 

 the mold in the laboratory. The bottles were then put in the refriger- 

 ator for two weeks. During this time scarcely any development took 

 place ; but after they were again placed in the laboratory, the myce- 

 lium pushed down into the ketchup and a new, very thin mycelium 

 developed on the surface. The filaments when seen under the 

 microscope were swollen, had irregular outlines, and a comparatively 

 smaller number of septa, and were filled with a coarsely granular pro- 

 toplasm. The ends were blunt and misshapen and the sterigmata 

 were irregular, tending more .toward a fasciculated arrangement, and 

 forming fewer conidia. The filaments from the vinegar and acetic 



