During September, 1907, ketchup was made in experimental batches to
determine whether it could be manufactured on a commercial scale
without the use of preservatives. These experiments were made to
determine (1) the keeping quality before opening the container and (2)
the length of time the product will keep without spoilage after the
bottle is opened.
The ketchup was made in a factory in which the conditions of
manufacture and all the surroundings were sanitary; whole, ripe
tomatoes, the same as used in the regular grade of canned goods,
were used and the formula and process were for a mild ketchup giving
the maximum of tomato flavor. Each batch consisted of 50 gallons of
finished goods, from which 1 gross of pint bottles was retained for
observation.
The term “regular ketchup” as used in these experiments means the
pulp of fully ripe tomatoes, to which was added granulated sugar,
80-grain, distilled vinegar, table salt, onions, garlic, whole
cinnamon, cloves, mace, and ground cayenne pepper. The pulp was cooked
in a steam-jacketed copper kettle for forty minutes and reduced
about 50 per cent. The finishing was done after cooking. The regular
bottles are pint sizes, washed in hot water, rinsed, and then heated
to a temperature of 190° F. for thirty minutes or more. The sterile
bottles referred to in the experiments were placed in a steam chamber
for twenty minutes at 230° F. The corks were sterilized by a bath in
paraffin at about 270° F. All of the work was accomplished quickly to
insure a smooth, even product with a bright, clean color. Acetic acid
extracts and oil extracts of spices were used in such quantities as
would give the same amount of spicing as when the whole spices were
employed.
In all of the following experiments the ketchups discussed were made in
September, 1907, and the last examination reported was made ten months
later, in July, 1908:
_Experiment No. 1._--Regular ketchup was made, but it was reheated
after finishing and bottled in sterile bottles at a temperature of
205° F. No spoilage has occurred at the end of ten months.
_Experiment No. 2._--Regular ketchup was made, and it was bottled
immediately after finishing in regular bottles at a temperature of
165° F. An after process was given at 190° F. for twenty minutes.
No spoilage has occurred after ten months.
_Experiment No. 3._--Regular ketchup was made, and was bottled in
regular bottles at 165° F., and given a subsequent process at 190°
F. for forty minutes. No spoilage has occurred.
_Experiment No. 4._--Regular ketchup was made, was bottled in
regular bottles at a temperature of 165° F., and given an after
process at 212° F. for twenty minutes. No spoilage has occurred.
_Experiment No. 5._--Regular ketchup was made, the same being
put up in regular bottles at a temperature of 165° F. and given
an after process at 212° F. for forty minutes. No spoilage has
occurred.
_Experiment No. 6._--Ketchup was made in which the acetic acid
extracts took the place of whole spices, and the bottling was done
at a temperature of 165° F., no after treatment being given. No
spoilage has occurred.
_Experiment No. 7._--Ketchup was made in which acetic acid
extracts were used, and the bottling was done at a temperature of
165° F. in sterile bottles. No after treatment was given and no
spoilage has occurred.
_Experiment No. 8._--Ketchup was made in which the oil extracts
were used instead of regular spices. The bottling was done in
regular bottles at a temperature of 165° F., no after treatment
being given. No spoilage has occurred.
_Experiment No. 9._--Ketchup was made in which oil extracts were
used instead of whole spices. The bottling was done at 165° F. in
sterile bottles, no after treatment being given. No spoilage has
occurred.
_Experiment No. 10._--Regular ketchup was made, but the pulp
was run through the sieving or finishing machine before instead
of after cooking, the object being to determine the effect upon
the character of the goods rather than upon the spoilage. This
practice could be followed to advantage in making all except the
very finest goods, and would give the same condition for bottling
as in experiment No. 1.
_Experiment No. 11._--Pulp was made in the usual manner and run
into barrels while just below the boiling point. The barrels
had been thoroughly washed and then steamed for twenty minutes.
As soon as the pulp had cooled slightly the bung was driven in
tightly and the barrel was rolled into storage. At the end of
sixty days the barrels were opened and the pulp was found to be in
good condition.
_Experiment No. 12._--Regular ketchup was drawn into 5-gallon jugs
which had been sterilized in the same manner as the bottles. These
were kept for sixty days and no spoilage occurred.