CANNED FRUIT, PRESERVES, AND JELLIES: HOUSEHOLD METHODS OF PREPARATION
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U. S. DEPARTMENT OF AGRICULTURE.
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FARMERS' BULLETIN No. 203.
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CANNED FRUIT, PRESERVES, AND JELLIES:
HOUSEHOLD METHODS OF PREPARATION.
BY
MARIA PARLOA.
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PREPARED UNDER THE SUPERVISION OF THE OFFICE OF EXPERIMENT STATIONS,
A. C. TRUE, DIRECTOR.
[Illustration: UNITED STATES DEPARTMENT OF AGRICULTURE]
WASHINGTON:
GOVERNMENT PRINTING OFFICE.
1917.
CANNING AND PRESERVING FRUIT.
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INTRODUCTION.
The common fruits, because of their low nutritive value, are not, as a
rule, estimated at their real worth as food. Fruit has great dietetic
value and should be used generously and wisely, both fresh and cooked.
Fruits supply a variety of flavors, sugar, acids, and a necessary waste
or bulky material for aiding in intestinal movement. They are generally
rich in potash and soda salts and other minerals. Most fresh fruits are
cooling and refreshing. The vegetable acids have a solvent power on the
nutrients and are an aid to digestion when not taken in excess.
Fruit and fruit juices keep the blood in a healthy condition when the
supply of fresh meat, fish, and vegetables is limited and salt or smoked
meats constitute the chief elements of diet. Fresh fruit is generally
more appetizing and refreshing than cooked. For this reason it is often
eaten in too large quantities, and frequently when underripe or
overripe; but when of good quality and eaten in moderate quantities it
promotes healthy intestinal action and rarely hurts anyone.
If eaten immoderately, uncooked fruit is apt to induce intestinal
disturbances. If eaten unripe, it often causes stomach and intestinal
irritation; overripe, it has a tendency to ferment in the alimentary
canal. Cooking changes the character and flavor of fruit, and while the
product is not so cooling and refreshing as in the raw state, it can, as
a rule, be eaten with less danger of causing stomach or intestinal
trouble. If sugar be added to the cooked fruit, the nutritive value will
be increased. A large quantity of sugar spoils the flavor of the fruit
and is likely to make it less easily digested.
Nowhere is there greater need of a generous supply of fruit than on the
farm, where the diet is apt to be restricted in variety because of the
distance from markets. Every farmer should raise a generous supply of
the kinds of fruit that can be grown in his locality. Wives and
daughters on the farms should find pleasure in serving these fruits in
the most healthful and tempting form. There are a large number of
simple, dainty desserts that can be prepared with fruit and without much
labor. Such desserts should leave the pie as an occasional luxury
instead of allowing it to be considered a daily necessity.
In the season when each kind of fruit is plentiful and at its best a
generous supply should be canned for the season when both fruit and
fresh vegetables are scarce. A great deal of the fruit should be canned
with little or no sugar, that it may be as nearly as possible in the
condition of fresh fruit. This is the best condition for cooking
purposes. A supply of glass jars does cost something, but that item of
expense should be charged to future years, as with proper care the
breaking of a jar need be a rare occurrence. If there be an abundance of
grapes and small, juicy fruits, plenty of juice should be canned or
bottled for refreshing drinks throughout the year. Remember that the
fruit and juice are not luxuries, but an addition to the dietary that
will mean better health for the members of the family and greater
economy in the cost of the table.
FRESH AND PRESERVED FRUIT FOR THE MARKET.
If the supply of fruit is greater than the family needs, it may be made
a source of income by sending the fresh fruit to the market, if there is
one near enough, or by preserving, canning, and making jelly for sale.
To make such an enterprise a success the fruit and work must be first
class. There is magic in the word "Homemade," when the product appeals
to the eye and the palate; but many careless and incompetent people have
found to their sorrow that this word has not magic enough to float
inferior goods on the market. As a rule large canning and preserving
establishments are clean and have the best appliances, and they employ
chemists and skilled labor. The home product must be very good to
compete with the attractive goods that are sent out from such
establishments. Yet for first-class homemade products there is a market
in all large cities. All first-class grocers have customers who purchase
such goods.
To secure a market get the names of several first-class grocers in some
of the large towns. Write to them asking if they would be willing to try
a sample of your goods. If the answer is favorable, send samples of the
articles you wish to sell. In the box with the fruit inclose a list of
the articles sent and the price. Write your name and address clearly.
Mail a note and a duplicate list at the time you send the box.
Fixing the price of the goods is important. Make it high enough to cover
all expenses and give you a fair return for your labor. The expenses
will be the fruit, sugar, fuel, jars, glasses, boxes, packing material,
wear and tear of utensils, etc., transportation, and commission. The
commission will probably be 20 per cent of the selling price. It may be
that a merchant will find that your prices are too high or too low for
his trade, or he may wish to purchase the goods outright. In any case
it is essential that you estimate the full cost of the product and the
value that you place on your labor. You will then be in a position to
decide if the prices offered will compensate you for the labor and
expense. Do not be tempted, for the sake of a little money, to deprive
your family of the fruit necessary to health and pleasure.
PACKING AND SHIPPING.
Each jar or jelly glass must be wrapped in several thicknesses of soft
paper (newspapers will answer). Make pads of excelsior or hay by
spreading a thick layer between the folds of newspapers. Line the bottom
and sides of the box with these pads. Pack the fruit in the padded box.
Fill all the spaces between the jars with the packing material. If the
box is deep and a second layer of fruit is to go in, put thick
pasteboard or thin boards over the first layer and set the wrapped jars
on this. Fill all the spaces and cover the top with the packing
material. Nail on the cover and mark clearly: GLASS. THIS SIDE UP.
The great secret in packing is to fill every particle of space so that
nothing can move.
PRINCIPLES OF CANNING AND PRESERVING.
In the preservation of foods by canning, preserving, etc., the most
essential things in the processes are the sterilization of the food and
all the utensils and the sealing of the sterilized food to exclude all
germs.
BACTERIA, YEASTS, AND FERMENTATION.
Over one hundred years ago François Appert was the first to make
practical application of the method of preserving food by putting it in
cans or bottles, which he hermetically sealed. He then put the full
bottles or cans in water and boiled them for more or less time,
depending upon the kinds of food.
In Appert's time and, indeed, until recent years it was generally
thought that the oxygen of the air caused the decomposition of food.
Appert's theory was that the things essential to the preservation of
food in this manner were the exclusion of air and the application of
gentle heat, as in the water bath, which caused a fusion of the
principal constituents and ferments in such a manner that the power of
the ferments was destroyed.
The investigations of scientists, particularly of Pasteur, have shown
that it is not the oxygen of the air which causes fermentation and
putrefaction, but bacteria and other microscopic organisms.
Appert's theory as to the cause of the spoiling of food was incorrect,
but his method of preserving it by sealing and cooking was correct, and
the world owes him a debt of gratitude.
In their investigations scientists have found that if food is perfectly
sterilized and the opening of the jar or bottle plugged with sterilized
cotton, food will not ferment, for the bacteria and yeasts to which such
changes are due can not pass through the cotton. This method can not be
conveniently followed with large jars.
Bacteria and yeasts exist in the air, in the soil, and on all vegetable
and animal substances, and even in the living body, but although of such
universal occurrence, the true knowledge of their nature and economic
importance has only been gained during the last forty years.
There are a great many kinds of these micro-organisms. Some do great
harm, but it is thought that the greater part of them are beneficial
rather than injurious.
Bacteria are one-celled and so small they can only be seen by aid of a
microscope. The process of reproduction is simple and rapid. The
bacterium becomes constricted, divides, and finally there are two cells
instead of one. Under favorable conditions each cell divides, and so
rapid is the work that it has been estimated that one bacterium may give
rise, within twenty-four hours, to seventeen millions of similar
organisms. The favorable conditions for growth are moisture, warmth, and
proper food.
Yeasts, which are also one-celled organisms, grow less rapidly. A bud
develops, breaks off, and forms a new yeast plant. Some yeasts and some
kinds of bacteria produce spores. Spores, like the dried seeds of
plants, may retain their vitality for a long time, even when exposed to
conditions which kill the parent organism.
Yeasts and nearly all bacteria require oxygen, but there are species of
the latter that seem to grow equally well without it, so that the
exclusion of air, which, of course, contains oxygen, is not always a
protection, if one of the anaerobic bacteria, as the kinds are called
which do not require oxygen, is sealed in the can.
Spoiling of food is caused by the development of bacteria or yeasts.
Certain chemical changes are produced as shown by gases, odors, and
flavors.
Bacteria grow luxuriantly in foods containing a good deal of nitrogenous
material, if warmth and moisture are present. Among foods rich in
nitrogenous substances are all kinds of meat, fish, eggs, peas, beans,
lentils, milk, etc. These foods are difficult to preserve on account of
the omnipresent bacteria. This is seen in warm, muggy weather, when
fresh meat, fish, soups, milk, etc., spoil quickly. Bacteria do not
develop in substances containing a large percentage of sugar, but they
grow rapidly in a suitable wet substance which contains a small
percentage of sugar. Yeasts grow very readily in dilute solutions
containing sugars in addition to some nitrogenous and mineral matters.
Fruits are usually slightly acid and in general do not support bacterial
growth, and so it comes about that canned fruits are more commonly
fermented by yeasts than by bacteria.
Some vegetable foods have so much acid and so little nitrogenous
substance that very few bacteria or yeasts attack them. Lemons,
cranberries, and rhubarb belong to this class.
Temperature is an important factor in the growth of bacteria and yeasts.
There are many kinds of these organisms, and each kind grows best at a
certain temperature, some at a very low one and others at one as high as
125° F., or more. However, most kinds of bacteria are destroyed if
exposed for ten or fifteen minutes to the temperature of boiling water
(212° F.); but, if the bacteria are spore producers, cooking must be
continued for an hour or more to insure their complete destruction.
Generally speaking, in order to kill the spores the temperature must be
higher than that of boiling water, or the article to be preserved must
be cooked for about two hours at a temperature of 212° F., or a shorter
time at a higher temperature under pressure. Yeasts and their spores
are, however, more easily destroyed by heat than bacteria spores. Hence,
fruits containing little nitrogenous material are more easily protected
from fermentation than nitrogenous foods in which in general
fermentation is caused by bacteria. Of course, it is not possible to
know what kinds of organisms are in the food one is about to can or
bottle; but we do know that most fruits are not favorable to the growth
of bacteria, and, as a rule, the yeasts which grow in fruits and fruit
juice can be destroyed by cooking ten or fifteen minutes at a
temperature of 212° F. If no living organisms are left, and the
sterilization of all appliances has been thorough, there is no reason
why the fruit, if properly sealed, should not keep, with but slight
change of texture or flavor, for a year or longer, although canned
fruits undergo gradual change and deterioration even under the most
favorable conditions.
When fruit is preserved with a large amount of sugar (a pound of sugar
to a pound of fruit) it does not need to be hermetically sealed to
protect it from bacteria and yeasts, because the thick, sugary sirup
formed is not favorable to their growth. However, the self-sealing jars
are much better than keeping such fruit in large receptacles, from which
it is taken as needed, because molds grow freely on moist, sugary
substances exposed to the air.
MOLDS AND MOLDING.
Every housekeeper is familiar with molds which, under favorable
conditions of warmth and moisture, grow upon almost any kind of organic
material. This is seen in damp, warm weather, when molds form in a short
time on all sorts of starchy foods, such as boiled potatoes, bread,
mush, etc., as well as fresh, canned, and preserved fruits.
Molds develop from spores which are always floating about in the air.
When a spore falls upon a substance containing moisture and suitable
food it sends out a fine thread, which branches and works its way over
and into the attacked substance. In a short time spores are produced and
the work of reproduction goes on.
In the first stages molds are white or light gray and hardly noticeable;
but when spores develop the growth gradually becomes colored. In fact,
the conditions of advanced growth might be likened to those of a flower
garden. The threads--mycelium--might be likened to the roots of plants
and the spores to the flower and seeds.
Mold spores are very light and are blown about by the wind. They are a
little heavier than air, and drop on shelves, tables, and floor, and are
easily set in motion again by the movement of a brush, duster, etc. If
one of these spores drops on a jar of preserves or a tumbler of jelly,
it will germinate if there be warmth and moisture enough in the
storeroom. Molds do not ordinarily cause fermentation of canned foods,
although they are the common cause of the decay of raw fruits. They are
not as injurious to canned goods as are bacteria and yeasts. They do not
penetrate deeply into preserves or jellies, or into liquids or
semiliquids, but if given time they will, at ordinary room temperature,
work all through suitable solid substances which contain moisture.
Nearly every housekeeper has seen this in the molding of a loaf of bread
or cake.
In the work of canning, preserving, and jelly making it is important
that the food shall be protected from the growth of molds as well as the
growth of yeasts and bacteria.
To kill mold spores food must be exposed to a temperature of from 150°
F. to 212° F. After this it should be kept in a cool, dry place and
covered carefully that no floating spore can find lodgment on its
surface.
STERILIZATION.
To sterilize a substance or thing is to destroy all life and sources of
life in and about it. In following the brief outline of the structure
and work of bacteria, yeasts, and molds, it has been seen that damage to
foods comes through the growth of these organisms on or in the food;
also that if such organisms are exposed to a temperature of 212° F.,
life will be destroyed, but that spores and a few resisting bacteria are
not destroyed at a temperature of 212° F., unless exposed to it for two
or more hours.
Bacteria and yeasts, which are intimately mixed with food, are not as
easily destroyed as are those on smooth surfaces, such as the utensils
and jars employed in the preparation of the food.
Since air and water, as well as the foods, contain bacteria and yeasts,
and may contain mold spores, all utensils used in the process of
preserving foods are liable to be contaminated with these organisms. For
this reason all appliances, as well as the food, must be sterilized.
Stewpans, spoons, strainers, etc., may be put on the fire in cold or
boiling water and boiled ten or fifteen minutes. Tumblers, bottles,
glass jars, and covers should be put in cold water and heated gradually
to the boiling point, and then boiled for ten or fifteen minutes. The
jars must be taken one at a time from the boiling water at the moment
they are to be filled with the boiling food. The work should be done in
a well swept and dusted room, and the clothing of the workers and the
towels used should be clean. The food to be sterilized should be
perfectly sound and clean.
As in this bulletin we have only to do with fruits, it will not be
necessary to say anything more about long cooking at a high temperature.
In canning fruits it is well to remember that the product is more
satisfactory if heated gradually to the boiling point and then cooked
the given time.
UTENSILS NEEDED FOR CANNING AND PRESERVING.
In preserving, canning, and jelly making iron or tin utensils should
never be used. The fruit acids attack these metals and so give a bad
color and metallic taste to the products. The preserving kettles should
be porcelain lined, enameled, or of a metal that will not form
troublesome chemical combinations with fruit juices. The kettles should
be broad rather than deep, as the fruit should not be cooked in deep
layers. Nearly all the necessary utensils may be found in some ware not
subject to chemical action. A list of the most essential articles
follows:
Two preserving kettles, 1 colander, 1 fine strainer, 1 skimmer, 1 ladle,
1 large-mouthed funnel, 1 wire frying basket, 1 wire sieve, 4
long-handled wooden spoons, 1 wooden masher, a few large pans, knives
for paring fruit (plated if possible), flat-bottomed clothes boiler,
wooden or willow rack to put in the bottom of the boiler, iron tripod or
ring, squares of cheese cloth. In addition, it would be well to have a
flannel straining bag, a frame on which to hang the bag, a sirup gauge
and a glass cylinder, a fruit pricker, and plenty of clean towels.
The regular kitchen pans will answer for holding and washing the fruit.
Mixing bowls and stone crocks can be used for holding the fruit juice
and pared fruit. When fruit is to be plunged into boiling water for a
few minutes before paring, the ordinary stewpans may be employed for
this purpose.
Scales are a desirable article in every kitchen, as weighing is much
more accurate than the ordinary measuring. But, knowing that a large
percentage of the housekeepers do not possess scales, it has seemed wise
to give all the rules in measure rather than weight.
If canning is done by the oven process, a large sheet of asbestos, for
the bottom of the oven, will prevent the cracking of jars.
The wooden rack, on which the bottles rest in the washboiler, is made in
this manner: Have two strips of wood measuring 1 inch high, 1 inch wide,
and 2 inches shorter than the length of the boiler. On these pieces of
wood tack thin strips of wood that are 1½ inches shorter than the width
of the boiler. These cross-strips should be about 1 inch wide, and there
should be an inch between two strips. This rack will support the jars
and will admit the free circulation of boiling water about them. Young
willow branches, woven into a mat, also make a good bed for bottles and
jars.
[Illustration: FIG. 1.--Wire basket.]
The wire basket is a saver of time and strength (fig. 1). The fruit to
be peeled is put into the basket, which is lowered into a deep kettle
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