Another test was made to determine whether the ketchup would spoil
when kept in a warm place, but not opened. Three bottles from each
experimental batch were placed in the incubator November 7, 1907, and
were kept there until December 23, 1907--forty-six days--and in that
time there was no sign of spoilage. They were then opened and kept in
the laboratory; the average number of days before spoilage occurred is
indicated in the following table:
_Average number of days before spoilage of ketchup after opening (kept
46 days at 95° before opening)._
---------------------------------------
Experiment No. | Days before spoilage.
---------------+-----------------------
1 | 2⅔
2 | 4⅔
3 | 3⅓
4 | 5
5 | 5⅓
6 | 4⅓
7 | 4⅓
8 | 4⅓
9 | 3⅔
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It will be observed that these samples spoiled in about the same length
of time as the bottles opened in February and tested in the incubator,
so that similar results were obtained by keeping unopened ketchup one
and one-half months at 95° F. and keeping it five months at 70° F. From
the results of the experiments it is evident that the ingredients of
the ketchup in the proportions used are not antiseptic, and it is also
apparent from the number of organisms found and the rapidity of their
multiplication that ketchup is a good, nutritive medium. Yeasts and
molds are the predominating organisms, and, as the ketchup is acid and
also contains sugar, and these organisms are found on tomatoes in the
field, their predominance in the ketchup is explained.