Chapter XII

.) The actual yeast, however, is what Fig. 30 shows it to be, a tiny, one-celled plant, increasing in number by the division of the single cell, or by the budding out of one cell from another. When conditions are favorable the yeast cells increase in number with great rapidity, and some of the sugar that is present is broken down into carbon dioxide gas and alcohol. It is this gas that causes the familiar bubbling when fermentation is taking place. We put yeast cells into bread and cultivate it for this gas. But how does it occur in canned fruits, when its presence is not desired? _Wild yeast_ floats in the air, and lies upon the surface of fruit. All cultivated yeast has been derived from wild yeast. In old-fashioned ways of bread-making no yeast was introduced, a soft dough being left in a warm place to ferment naturally, the yeast cells probably being present in the flour. The yeast that spoils the canned fruit is present in the fruit, in the utensils, or can, and has not been killed as it should be in the canning process.

[Illustration: FIG. 29.——One form of yeast. _Buchanan’s Household Bacteriology_]

[Illustration: FIG. 30.——A yeast cell. _a_, cell wall. _b_, vacuole. _c_, granules. _d_, nucleus. _e_ and _e_, buds. _Buchanan’s Household Bacteriology._]

[Illustration: FIG. 31.——The four types of bacterial cells. _A_, cocci. _B_, bacilli. _C_, spirilía. _D_, branched filamentous organism. _Buchanan’s Household Bacteriology._]

The _bacteria_ are also one-celled microörganisms, smaller than the yeast. Figure 31 shows the four types of bacterial cells. Their size is measured by the unit used in the microscope, called the micron, which is about 1/25000 of one inch. Bacteria may measure from one to three or four of these microns in length. Some bacteria are reproduced by means of spores which form within the cell. Bacteria, as they develop in some material, produce substances from the material that may or may not be injurious to us. One important truth about the bacteria is this: that many of them are harmless, and may even be made useful, as in the manufacture of fruit vinegar. The pleasant acid of buttermilk and of sour milk is due also to bacteria which are not harmful to us. However, there may be disease producing bacteria present in milk that is not clean, and their presence must not be tolerated. Other bacteria, developing in meat and fish, produce substances known as _ptomaines_, which are dangerous poisons; or, more often, the kinds of bacteria which thrive in meats and fish may themselves be directly injurious to man.

It is evident, therefore, that the problem before us is the control of these lower organisms, that we may increase or destroy them as we will.

=The control of microörganisms.=——With warmth, water, and food all living things flourish and grow; most organisms require air, but some of the microörganisms do not. Where these conditions are best met, the organism is most active and multiplies most rapidly. To retard growth or to destroy life, the conditions must be the reverse of favorable. While warmth, say a temperature from 70° to 90° F., promotes the life of most microörganisms, intense heat destroys it. The boiling temperature, 212° F., will kill these lower organisms, although this heat has to be continued for some length of time, particularly in the case of spores. The spores of certain bacteria are quite resistant. A temperature of 32° F. and lower retards growth, but it requires extreme cold to destroy bacteria. Since moisture is necessary to all the lower organisms, they do not develop in a dry material or dry place.

We cannot destroy these lower forms of life by removing food from them, since they are ever present, but we can make the food unavailable to them through the introduction in the material of certain substances called preservatives which prevent their growth. The preservatives long familiar are salt, sugar, wood-smoke, spices, vinegar, and alcohol. While a small amount of sugar is necessary in the fermentation process, a large amount acts as a preservative, as in candied fruit. It is an interesting fact that alcohol and vinegar, products of fermentation processes, tend (when sufficiently concentrated) to stop the growth of the fermentation organisms.

To the reader who desires a fuller account of the bacteria, yeast, and molds, especially as related to household affairs, Buchanan’s “Household Bacteriology” is recommended as the most recent and satisfactory book in this field.

=A word about buying canned goods.=——When canned goods are put up in large quantities at the factory, abuses are likely to exist. Poor, even decayed, fruit may be used, the whole process may be unclean from beginning to end, and undesirable preservatives or an excess of sugar or spice may be introduced to cover the use of poor materials or methods. The condition of the worker in the cannery is one of the important industrial problems at the present time. Unhappily, poor conditions do often exist in canneries that turn out a cheap product. On the other hand, there are firms that may well take pride in their system from beginning to end.

=Serving canned food.=——All canned food should be exposed to the air for a short time before serving, and stirred that the material may be aerated. This partially removes a certain flatness of taste. Canned fruit is improved by reheating, even.

When possible, vegetables bought in a tin can should be washed in the colander before they are heated. This greatly improves the flavor.

=Principles of preservation.=

Sterilization of food and all apparatus by the boiling temperature, 212° F.

The removal of moisture by some drying process.

The addition of a preservative.

Sealing, to prevent the entrance of air.

=Practical methods.=

_Canning._——Fruit or vegetables sterilized at 212° F. and tightly sealed in jars or cans.

_Preserving._——Whole fruit, sterilized, large amount of sugar added, and sealed or covered in jars.

_Jam making._——Fruit broken up, sterilized, sugar added, and covered.

_Jelly making._——Fruit juices, sterilized, sugar added, covered.

_Pickling._——Fruit and vegetables sterilized, vinegar, spices, and sugar the preservatives used.

_Drying._——Fruits and vegetables protected from dust and insects, and slowly dried by the sun’s heat or artificial heat.

[Illustration: FIG. 32.——Preserving kettles in a large factory. _Courtesy of H. J. Heinz Co._]

=Apparatus.=——Scales. Quart measure. A preserving kettle of good enamel ware. Plated knives. Large spoon of enamel or wood. Tablespoon and table fork. Pint and quart cans with glass tops fastened by springs. New rubber rings. Jelly glasses with covers. Cloth jelly bag. Stick on which to hang the bag. Large bowl. Boiler, in which to stand the cans. A funnel. A dipper. Old towels, or cheap cloths. Saucer and spoon for testing.

GENERAL METHODS AND RECIPES

=General directions.=——Thoroughly wash all the utensils, just before using. Sterilize the cans and glasses by placing them in a large kettle or boiler on the stove, covering them with cold water, and allowing the water to reach the boiling point and to boil for half an hour. Covers and rubber rings should be treated in the same way.

[Illustration: FIG. 33.——Picking over strawberries. _Courtesy of H. J. Heinz Co._]

Prepare the fruit by careful washing, picking over, paring and cutting.

The skins may be loosened on peaches and tomatoes by pouring hot water over them.

Weigh both fruit and sugar, or measure if no scales are available.

See that the cooking apparatus is in good order, that the proper heat may be continued.

Avoid rapid boiling of the fruit.

Place the cans when they are to be filled with hot fruit upon a towel wet in very hot water, or in a pan holding an inch or so of hot water. Never hold the can or glass in the hand.

Use a dipper for putting cooked fruit into the can. A funnel is useful placed in the mouth of the jar.

Put whole fruit and halves compactly in the jar, using tablespoon and fork, or two tablespoons. It requires practice to do this well.

See that all air bubbles are removed, and fill the cans to overflowing, before putting on the glass tops and fastening on the spring. Wipe off the jars, carefully, and stand them on their tops for a day in order to test the tightness of the rubbers and the fastening.

After filling jelly glasses, set them at one side, and cover them all with a piece of cheesecloth, until the jelly becomes firm. Then pour melted paraffin upon the jelly in each glass, and when the paraffin is cooled, put the covers on firmly.

Label the jars with the name of the fruit and the date of the preserving before putting them away.

=Canning.=

_Method 1._——Material cooked before it is put into the can. This is a good method for berries, and for fruit that will be served as a sauce. Proceed in the preparation and finishing according to the general directions. Cook the fruit gently for half an hour. Use as little water as possible. No sugar is _required_ in the canning process, but the flavor is better if a small amount is used in the beginning, a half cup of sugar to a pound of fruit.

_Method 2._——Material cooked in the can. This is the better method for whole fruit and halves. Select firm, well-shaped fruit for this method, rejecting the mellow and soft fruit. Pack the cans tightly with the fruit, and pour in hot water with sugar dissolved in it, a half cup to the quart can. More sugar can be used, if so desired. Set the jars in a boiler on a rack, and surround them with warm water, to a height that will not allow the water to boil into the cans.

Set the cover on each jar, but do not fasten them. Cover the boiler closely, bring the water to a boil, and allow it to boil for an hour. At the end of this time, test the fruit for tenderness with a fork, pour in more sirup if it is necessary. Remove the jars when the water has cooled sufficiently, and adjust the covers. Cold water is sometimes used at the beginning, but this makes the process longer.

This is a good method also for the canning of whole vegetables like peas and asparagus. The cooking of vegetables should continue for at least two hours, and three hours are better for peas and string beans.

Apparatus is constructed for this method of canning, but the ordinary boiler answers the purpose.

=Preserving.=

A good method for peaches, apricots, and quinces. Select firm and handsome fruit and prepare it carefully. Allow a pound of sugar to a pound of fruit. (What is the measure of a pound of sugar?) Place enough water in the kettle to cover the fruit, dissolve the sugar in the water, put the fruit into the kettle, and cook very gently until the fruit becomes a clear color. Rapid boiling spoils the shape of the fruit. Do not stir at all, but skim off any scum that rises to the top. When the fruit is done, put it with great care into the jars. If the sirup is thin, boil it down for a short time, and then fill the jar. Close the jar as in canning.

This is a difficult process for beginners.

=Jam making, and fruit butter.=

This is the most economical of the preserving processes and the easiest for the novice. It is nothing more than a fruit sauce, with a larger amount of sugar than usual to assist in its preservation.

Soft and somewhat imperfect fruit may be used. If in the basket of fruit bought for canning or preserving there are some fully ripe or poorly shaped specimens, these may be used for jam. For jam proper allow a pint of sugar to a pound of fruit. Cook the fruit with enough water to prevent its sticking to the kettle, using as little as possible.

Mash the fruit by stirring it occasionally as it cooks. When the fruit is soft, add the sugar, stir thoroughly, and cook gently for about five minutes. Test by cooling a spoonful on a saucer. The jam should thicken slightly. When ready, pour it into jelly glasses, or somewhat larger earthen jars——“jam pots.” Seal, as directed for jelly.

The _fruit butter_ is even more like fruit sauce than is the jam, for it is softer than jam, and contains less sugar. A cup or only a half cup of sugar to the pound of fruit is enough. Proceed exactly as in jam-making.

_Apple butter_ may be flavored with spices, with ginger root and lemon juice, and with other fruits. One or two quinces or a slice of pineapple cooked with the apples gives a pleasing variety. Exercise the inventive faculty here.

=Jelly making.=

There is another principle involved in jelly making in addition to the principle of preservation. Fruit contains a substance known as pectose, one of the carbohydrates, that partially solidifies the fruit juice when the water in the juice is

## partially evaporated. The addition of sugar helps in this

process, but no amount of sugar will set the jelly if the pectose is not present. Some fruits have more than others, and also more when not over-ripe. Currants and firm apples are good jelly makers, and serve as a basis for other fruits that do not jelly well. Mellow summer apples do not set well. Crab apples are excellent for this purpose.

There is another step in this process, the straining out of the juice from the pulp. For this, prepare a jelly bag from firm cotton cloth which has been boiled and washed. This bag must be hung in such a way that the juice drops from the point of the bag into a bowl below. It may be hung upon a stick between two chairs, or upon the rod of a strong towel rack over a table.

1. =Apple jelly.=

Select tart, red-skinned apples, cut them in small pieces with the skins on, retain the cores, and put them in a kettle with cold water to barely cover. When thoroughly cooked and mashed, put this pulp into the jelly bag, and allow the juice to drip as long as it will. Do not squeeze the bag, nor stir the pulp if you wish clear jelly. This dripping process is a matter of hours, and in the home kitchen may continue all night. Allow a pint of sugar to a pint of juice. Return the juice to the kettle, and allow it to simmer for twenty-five minutes or half an hour, skimming when necessary. In the meantime, heat the sugar, being careful not to melt or burn it. Stir the sugar gently into the juice, and boil five minutes. Test a little upon a saucer. It should show signs of jellying as it cools. Boil longer, if necessary. Finish as directed. Jelly often does not set until twenty-four hours have elapsed.

=2. Currant jelly.=

The method is the same as with apple jelly. It is not necessary to remove the currants from the stem. Heat just long enough before the straining to make the juices flow well.

Very agreeable flavors are secured by the combining of two or more fruits in a jelly; quince and pineapple with apple;——a leaf of rose geranium or lemon verbena in a glass of apple jelly; raspberry with currant. White apple jelly may be flavored with mint leaves, and used in place of mint sauce with meat.

=Pickling.=

Pickles are not desirable in the diet. If acid is craved, it is much wiser to secure it by fresh fruits, and by the use of lemon juice.

=Drying.=

This process should not be discarded if there is a supply of fruit in the orchard or garden. Place thinly sliced apples and peaches upon plates or trays, protect by clean cheesecloth, and dry in the sun. The color may be dark, but the flavor is excellent.

_Laboratory management._——The fruit selected for use in the school kitchen depends upon the time of year. The autumn is the season for preserving, but some fruit is available at any time of year: in the winter, apple and peach butter from the dried fruit; in the spring rhubarb jam or jelly; in the late spring or early summer, strawberry jam. If the school program and the equipment permit the serving of meals by the class, fruit may be preserved in the fall for these occasions.

EXERCISES

1. Explain the value of fruit in the diet.

2. Why is cooked fruit sometimes better than raw?

3. Inquire the price of fresh fruit in the market, and compute the cost of a 100-Calorie portion of two of the most common and cheapest.

4. The same with one or two of the dried fruits.

5. What are the important points in the preparation of fresh fruit for the table?

6. What changes are effected in baking an apple?

7. What are the principles of the preservation of food?

8. What is meant by a preservative?

9. What is meant by sterilization?

10. What is mold? Decay? Fermentation?

11. What are the important points in canning?

12. What is the difference between canned fruit and “preserves”?

13. How does jelly making differ from the other processes?

14. What is one of the most important points in cooking dried fruits?

15. Find the cost of a can of peaches at the grocery. Weigh the contents and count the peaches. Compare with the cost of an equal amount of home-canned peaches. What points in the problem must be taken into account?

16. The same problem with jelly bought at the grocery and made at home.

17. Work out the problem of estimating the comparative cost of canned peaches and dried peaches, when calculated to the same food value.

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