EXPERIMENTS ON THE SPOILAGE OF TOMATO KETCHUP
TEXT
TEXT
PAPER
Color reddish brown; greasy odor; many oil globules; too many mold
filaments and bacteria for sound tomatoes. Price 20 cents.
_No. 113._--Another bottle of the same brand examined in April,
1908; said to have been manufactured in 1908; no preservative
mentioned; not spoiled after standing open for seventy days; same
as No. 18 in color and odor; oil and many fungi again present.
_No. 10._--Opened September 2, 1907; age unknown; half-pint
bottle; no preservative mentioned; not spoiled July 6, 1908. A
neck label 2 inches in height guaranteed the highest quality; an
extra label lower down on the neck stated the product to be the
natural color, and made from fresh, ripe tomatoes; the regular
label carried the brand, manufacturer’s name, etc. Color brown;
sweetish odor; colonies of mold; distorted filaments; many
bacteria; a few small oil globules. Price 25 cents.
_No. 106._--Same brand; pint bottle; examined in April, 1908; said
to be manufactured in 1907; color red, discolored near surface;
2-inch neck label in addition to regular label; no preservative
mentioned; did not spoil in seventy days; oil globules; particles
of red, amorphous matter; whole colonies of mold, as well as
fragments of filaments; teeming with bacteria.
_No. 77._--Different brand, but same manufacturer as Nos. 10 and
106; age unknown; pint bottle; one-twelfth of 1 per cent of sodium
benzoate declared; opened December 1; placed in incubator at 95°
F. for a month; not spoiled July 6; color reddish brown; greasy
odor; oil globules, many mold filaments, and bacteria present.
Price 20 cents.
_No. 107._--Third brand from same manufacturer as preceding; said
to be manufactured in 1907; half-pint bottle; one-twelfth of 1
per cent of benzoate of soda declared; layer of oil on surface;
sweet odor; reddish-brown color. Oil globules prominent feature
microscopically, whole colonies of distorted mold were present,
and sample contained many different forms of bacteria. Price 10
cents.
_No. 14._--Opened September 2, 1907; age unknown; no preservative
mentioned; not spoiled July 6, 1908; half-pint bottle; color red;
good odor; few bacteria; free from refuse. Price 25 cents.
_No. 108._--Same brand as No. 14; said to be manufactured in 1907;
pint bottle; one-tenth of 1 per cent of benzoate of soda declared;
color red; good odor; few fungi; clean and free from refuse.
_No. 33._--Opened October 24, 1907; age unknown; one-tenth of 1
per cent of benzoate of soda declared; spoiled November 1; pint
bottle (14 ounces); sweetish odor; brown color; many molds, yeast
and bacteria. Price 10 cents.
_No. 114._--Same brand as No. 33; said to be manufactured in 1907;
opened in April; not spoiled in seventy days; many molds, yeasts,
and bacteria; some green tissue, and filaments of algæ. The price
was 10 cents.
SUMMARY.
1. The experiments made during the season of 1907 on the manufacture
of tomato ketchup without chemical preservatives were conducted under
factory conditions and upon a commercial scale. The results prove that
such a ketchup can be made and delivered to the consumer in perfect
condition; the product in question having already stood ten months,
unopened, without showing the slightest indication of spoilage.
2. The product is of excellent consistency, flavor, and color. The
formula employed regularly in the factory where the experiment was
conducted was used, but other recipes could be adapted without changing
the character of special brands. In the manufacture of such a product
the following precautions were observed:
(_a_) Whole, sound, ripe tomatoes and high-grade salt, sugar, vinegar,
and spices were used; care and cleanliness were observed at every
step of the preparation, and the preservation accomplished by heat in
the following manner: The pulp was cooked in a steam kettle for about
forty minutes, until the mass was reduced to about one-half its volume.
Additional processing after bottling did not appear to be necessary to
keep the ketchup before opening, and had no effect in these experiments
in delaying spoilage after opening.
(_b_) Ketchup was bottled directly from the cooker at a temperature
of 205° F. in bottles prepared in two ways: (1) Sterilized in a steam
chamber at 230° F.; (2) Washed in hot water, rinsed, and heated to 190°
F. in a dry heat for at least thirty minutes. Ketchup was also bottled
after the usual process of sieving at 165° F. in bottles prepared in a
similar manner. The corks for all bottles were sterilized in a paraffin
bath at 270° F. The same ketchup which was bottled at 165° F. was also
given subsequent processing at 190° F. and 212° F. for twenty and forty
minutes. All have kept without spoilage.
3. Some of the condiments have a limited antiseptic value, but can
not be depended upon to prevent spoilage in the quantities used for
flavoring. While sugar and vinegar can be added in such amounts as
to delay the appearance of molds, and cinnamon and cloves can be
depended upon to check deterioration to some extent, these condimental
substances have only an incidental value for this purpose.
4. The spoilage of ketchup after opening depends more upon the
temperature of the place in which it is kept than on any variation
in the manner of processing. Fresh ketchup held, after opening, at a
temperature of 95° F. kept for five days on an average without any
trace of mold appearing; at 72° it kept for six days; at 67° for eight
days; about 46° (refrigerator), fourteen days; and at from 30° to 60°
for twenty-seven days. These figures represent the time at which the
first trace of spoilage occurred in the neck of the bottle--had this
been removed the figures would be much increased--and by no means
represent the maximum time during which the ketchup could have been
used, the maximum figures, even under these conditions of observation,
varying from eight to fifty-eight days. The keeping of the ketchup
in warm storage at 70° for one hundred and fifty days before opening
hastened the average time of spoilage after opening about one day. The
advisability of using small containers, to get the best results with a
first-class ketchup, is apparent.
5. Sodium benzoate, even when used in the proportion of 0.1 per
cent, is not always effective, and has an injurious effect upon the
living matter of the molds, shown by the distortion and swelling of
the filaments, which are filled with a coarse granular protoplasm
containing much fat.
6. Artificially colored ketchup can be detected under the microscope
by the fact that certain tissues, normally colorless, are dyed red, or
by the presence of fine, red, amorphous particles which do not go into
solution.
7. Ketchup made from whole ripe stock in a cleanly manner gives a clean
appearance under the microscope, but few molds, yeasts, and bacteria
being present. On the other hand, ketchup made from trimming stock,
or from tomatoes that have been allowed to spoil, contains immense
quantities of these growing organisms which may be killed in the
process of manufacture, but still give proof of the character of the
material used. Ketchup as ordinarily made from trimming stock should,
therefore, be designated, so as to differentiate it from that made from
sound fresh tomatoes, as the two products are radically different.
This exactness in labeling is due no less to the manufacturer than to
the consumer, as it is impossible to make the superior product in fair
competition with the inferior one, other conditions being equal, unless
the two are properly designated, there being naturally some difference
in the price.
Transcriber's Notes:
In the text version, italics are represented by _underscores_.
Missing or incorrect punctuation has been repaired.
The following corrections have been made to the text:--
p.8. A majority of the manufacturers employ word, has been changed to
A majority of the manufacturers employ the word.
p.28. one has has, the duplicate has been removed.
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