The preservation of fruit and other foods has been a household industry for generations, and it is now an important commercial industry. The old-time farm had its smokehouse where hams and beef were “cured,” the barrel of brine stood in the cellar for pork and corned beef, apples and corn were dried for winter use, and rows of preserve jars stood upon the shelves. Food was preserved by simple processes long before the reason for the decay and spoiling of food was fully understood, but with larger knowledge and better appliances, we now preserve food more effectively and in quantities larger than were possible in former days.
Fruit is the food material now most commonly preserved in the home kitchen. Vegetables need to be subjected to heat for a much longer time than fruit, and many people prefer to buy canned vegetables rather than to go to the trouble and expense of canning them at home. Where there is an oversupply of vegetables in the home garden, it is sometimes economy to can them, and this may be done if care is exercised. The cost of fuel and labor must be counted in, when studying the question of home preserving versus buying the canned product.
Whatever the food material, and the process, the principles of preservation are the same for all.
Why does food spoil?—The decay and moldiness of fresh fruit are matters of common observation; and the housekeeper knows that mold is liable to cover the top of a jelly glass, and that a can of fruit will ferment at times, even to the point of bursting the can.
We recognize another kind of deterioration in meat and fish that have become tainted, even when no mold is visible, and there is no opportunity for ordinary fermentation. The microscope has given us eyes to see, and as a result of the patient work of the scientist with this instrument we now know that the difficulties in keeping food are caused by the presence of minute vegetable organisms known as molds, yeasts, and bacteria. It is impossible in some cases to draw a sharp line between these different forms of lower life, yet we are able to distinguish them sufficiently for practical purposes.
Masses of mold that can be seen with the naked eye are distinguished by a feathery appearance and bright color. Figure 28 shows three species of the green mold that affects jam and jellies. Other species are found in Roquefort and Camembert cheese, and give the flavors characteristic in these cheeses.
The presence of yeast can be detected by its action, but it cannot itself be seen without the microscope. When canned fruit or homemade fruit juice “works,” yeasts cells are present in great number. Figure 29 shows one form of yeast, highly magnified, and Fig. 30 shows a single yeast cell. The yeast cake is a mixture of thousands of such cells with some flour or flour and meal, and the cells lie dormant in the cake, until we are ready to use them in bread. (See 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.
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.
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.
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.
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.
CHAPTER VII
The distinction between the fruit and the vegetable is purely arbitrary, since both are parts of plants and have the same general composition. Botanically the tomato is as truly a fruit as the apple; but when it is stewed and served with meat, it is classed as a vegetable. Other parts of plants, however, besides the fruit are used as vegetables.
Composition and nutritive value.—Vegetables are much like fruits in composition, being richest usually in carbohydrates and ash, but sometimes containing a large amount of protein. Some have carbohydrates in the form of starch, as the potato, and others in the form of sugar, as the beet; young corn is rich in sugar, old corn in starch. All have more or less cellulose, that in lettuce being very tender, while that in beets is so firm as to be softened only by long cooking. Study carefully Figs. 34 and 35. Notice how the amount of water compares with the amount in fruits. See, too, that beans, both green and dry, are richer in protein than other vegetables. Celery has the highest percentage of water, and is valuable for its ash and the bulk it gives because of the large amount of cellulose.
To explain these facts we must understand something of the physiology of the plant. The stem is the carrier of water and nutritive material to other parts of the plant. The onion bulb, the parsnip root, and the potato tuber are the winter storehouses of food for the next year’s plant when the leaves first sprout. In the dry bean seed, and also in the pea and lentil, the young plant lies dormant, with a large supply of all the foodstuffs ready for its first growth when warmth and moisture are supplied in the spring. Classified according to their nutritive value, the vegetables rank as follows. Leaves are grouped with stems.
| The seeds | Contain all the foodstuffs. High in protein. |
| Roots and tubers and the bulb | Contain all the foodstuffs. Low in protein and fat. High in starch or some form of sugar. |
| Rinds (squash and pumpkin) | Contain all the foodstuffs in small amounts. Mineral content the chief value. |
| Leaves and stems | Mineral content the chief value. |
Certain substances in some vegetables are supposed to have a physiological effect, but we should be cautious in accepting statements that have not been scientifically proved; for instance, that celery is “good for the nerves.” It is doubtless true that the oils which give onions and the cabbage their strong flavors do not agree with some people, and these vegetables should be eaten with caution.
How to buy.—Much interest is added to the study of vegetables by the examination of a seed catalogue easily obtainable from a firm selling seeds and plants. In this way, one may increase one’s knowledge of varieties for planting in the home garden, even if they are not common on the market. City markets offer an increasing variety of vegetables, and the purchaser should not hesitate to buy a vegetable because it is new to her. An inexpensive Italian vegetable, fenucchi, is now sometimes found on sale, and its characteristic flavor is very agreeable.
| KIND | WEIGHT OF PORTION, OUNCES |
| Asparagus | 16 |
| Beets | 10 |
| Cabbage | 13 |
| Carrots | 10 |
| Corn | 9 |
| Cucumbers | 20 |
| Lettuce | 22 |
| Onions | 8 |
| Potatoes | 5 |
| Spinach | 15 |
| Tomatoes | 15 |
The season of vegetables is so extended by canning, by the shipping of vegetables from the South, and by growing under glass that there is always a wide range of choice. There are in winter, however, some tempting delicacies in the way of green vegetables that the buyer with a limited purse should pass by. A cucumber at fifty cents or even at ten cents is not a sensible purchase. Lettuce, grown under glass, at ten cents a head is not an extravagance, if the income allows thirty-five to forty cents per capita per day for food. As a rule, select the less expensive vegetable, provided it is in good condition. The prices are so fluctuating that a definite statement is impossible. (See Chapter XVII.)
Root vegetables should be uniform in size, sound, the skins fair.
Head vegetables should be solid, with but few waste leaves on the outside.
Vegetables with hard rind should be sound and firm.
Asparagus should be even in size, the stalks not bitten by insects.
Cauliflower should be firm and white, not affected by insects or blight.
Celery should be firm and white, free from blemishes, fine in texture.
Peas should have crisp pods well filled, but not too full.
String beans should be crisp and snap easily.
All leaf vegetables should be crisp—not wilted.
GENERAL METHODS AND RECIPES
Uncooked vegetables.—Crisp vegetables with tender fiber are eaten raw. Their preparation includes freshening in cold water, thorough washing to remove grit and insects, thorough drying by shaking in a soft cloth or wire basket, and cooling on the ice. Lettuce should not be served so wet that the water collects on the plate, making it impossible to dress the salad with oil. See salad making, Chapter XV.
Cooked vegetables.—Vegetable cooking is an art much neglected, and in consequence vegetables are sometimes served lacking their proper flavor and their original nutrients. To cook vegetables in boiling salted water, throwing the water away, is not the correct method, except in a few cases. With this method much of the valuable mineral matter and the flavoring substances are lost in the water. With such strong flavored vegetables as the cabbage, old onions and beets, and old potatoes this method is permissible, but even in these cases the nutritive value is decreased.
Principles of cooking.—Softening of the fiber.
Opening of the starch granules, when starch is present, at a temperature of 212° F. Retaining mineral and flavoring matters.
Cooking processes.—These rank in value as they do or do not retain the mineral and flavoring matters.
Baking.—No nutritive material lost. The best method for potatoes and sweet potatoes. Used also for squash, pumpkin, beets, young onions, dried beans, peas, and lentils.
Steaming. (Cooking in a steamer.)—No nutritive material lost. A good method for all fresh vegetables. Steamed vegetables have less flavor than baked.
Stewing.—Cooking in a stew pan or kettle with so little water that it is almost boiled out at the end of the process, any remaining liquid being served with the vegetable. The best method for spinach, which can be cooked with no additional water, beyond that remaining on the leaves from the washing. The French use this method almost entirely, and with tender peas and carrots they omit water and use butter only. A substitute for this latter is a very small amount of water, with the addition of butterine or some good butter substitute.
Boiling.—Cooking in a large amount of boiling, salted water, the water to be drained off and thrown away. May be used with old beets of rank flavor, strong onions, old potatoes, or potatoes boiled with the skins on. A wasteful method.
Adjuncts.—Salt, pepper, butter, or some other fat, milk, cheese, bread crumbs, parsley, eggs.
Utensils.—A vegetable brush, a sharp knife, a chopper, a potato masher, a strainer, a colander, a stew pan, kettle or steamer, baking pan, baking dish, bean pot, frying pan or kettle.
General directions.—Wash the vegetables, scrubbing the skin vegetables with a brush. Washing in several waters is important with spinach to remove all grit. Scrape off thin skins or pare off the thicker. Thick skins such as those of old beets are more easily removed after cooking. The outer covering must be removed in the case of peas, shell beans, and sweet corn. Pull or cut strings from string beans with great care. Discard all poor portions. Remove and throw away the inner pulp and seeds of old squashes and pumpkins. The whole of a tender summer squash is eatable.
When boiling salted water is used, allow one tablespoonful of salt to four quarts of water. Steamed and stewed vegetables are salted and dressed with butter or butter substitute before serving. Butter is a better dressing for vegetables than white sauce. Where cream is available, nothing is so delicious. Use white sauce very sparingly with some escalloped vegetable for variety. Making a sauce adds to the labor of preparation, and the sauce hides the delicious flavor of a well-cooked vegetable. Some vegetables are mashed before serving; potatoes, turnip, squash, either boiled or baked.
Time of cooking.—The following table is a guide, but one must learn from practice, for the time depends upon the quality of the vegetable, whether tender or tough, and upon the size whether large or small. Test by gently inserting a fork.
Allow more time for cooking in a steamer, than for stewing or boiling. It requires more time to bake a potato than to boil one of the same size. Why?
(For stewing and boiling unless stated otherwise.)
Fifteen minutes.—Tender cabbage and sweet corn. These are usually cooked too long.
Thirty minutes.—Asparagus; peas; potatoes of medium size; summer squash; tomatoes.
Forty-five minutes.—Young beets and carrots; onions; young parsnips; medium potatoes baked, sweet potatoes boiled.
One hour.—String and shelled beans; cauliflower; oyster plant; winter squash, steamed or baked; young turnips.
Two hours.—Old carrots, beets, and turnips.
Six to eight hours (or more).—Dried beans, lentils, and peas, baked in the oven, with water added.
The potato, a starchy vegetable.—Make it your pride to serve a plain potato, mealy and inviting. Potatoes are “new,” fully ripe, and old. The new potato is in market in July and August, and may be recognized by its very thin skin. The later potatoes have a thicker skin, the color still being fresh. In the spring after its winter storage, the potato is “old.” It seems a little less firm, the color of the exterior is somewhat changed; perhaps the buds in the eyes of the potato are beginning to grow. When cooked it has a stronger flavor, and rather darker color. If the potato has been frozen, a sweet flavor is developed, and the quality is waxy. Potatoes are sometimes inferior in quality when the season is a poor one, or when some potato disease is prevalent. The following classification shows you in how many ways potatoes may be cooked, and also shows you how easy it is to classify recipes in an orderly way.
If you know some other method, see if you can fit it into this grouping.
Laboratory management.—The last experiment is the only one not easily performed in the school kitchen. The process, can begin perhaps on one day, and be finished the next. If there is some apparatus that cooks at a low temperature, the practical difficulties may be overcome.
Vegetable, or “cream” soups.
These are of two classes: the purées (porridge), or thick soups, with vegetable pulp as the thickening material, and the cream soups, which are somewhat thinner, the juices of some vegetable giving the flavor.
Potato purée, or soup, is an example of the first; cream of tomato of the second. The line is not sharply drawn between the two in many cook books. Milk is an important ingredient in these soups, so that they are sometimes known as milk soups. Butter and flour are used in both,—the flour in the purée “binds” the mixture and makes it smoother; in the cream soup the flour is used for thickening as well.
Dried beans, peas, or lentils make a delicious purée, the secret of success being long slow cooking in some low temperature apparatus. They are brought to perfection in the Atkinson Cooker.
- Potato 1 cup
- Milk 1 quart
- Flour 1 tablespoonful
- Butter 1 tablespoonful
- Salt 2 teaspoonfuls
- Celery stalks, cut small 1 teaspoonful
- Onion, chopped 1 tablespoonful
- Pepper, Cayenne To taste.
Remarks.—If a thicker purée is desired, use more of the mashed potato. If celery salt is used, omit one teaspoonful of the salt. Less onion may be used, and the pepper omitted.
Utensils.—Make the list yourself, after reading the directions for mixing.
Method of mixing.—Boil and mash the potato, or use cold mashed potato. Heat the milk in the double boiler with the celery and onion. Add the milk gradually to the mashed potato, beating vigorously.
Put this mixture through a strainer into the double boiler, and reheat it. Melt the butter in a small saucepan, or stir in the flour, add slowly half a cup of the soup to the butter and flour paste, and then pour this slowly into the mixture in the double boiler, stirring all the time. The soup will be ready to serve in about ten minutes.
The important point in this recipe is the quality of the mashed potato. It should be dry and light. It may be made from hot, mealy baked potatoes. If cold mashed potato is used, this should be made light again with a fork. An excellent luncheon dish. Will serve four to six people.
- Tomato juice 1⁄2 cup
- Milk 1 quart
- Flour 2 tablespoonfuls
- Butter 2 tablespoonfuls
- Salt 2 teaspoonfuls
- Bicarbonate of soda 1⁄2 teaspoonful
- Pepper, Cayenne To taste.
Remarks.—Celery and onion may be added, but are not necessary. When you become expert, you will be able to use a larger amount of tomato juice, and even omit the soda.
Method of mixing.—This you will be able to work out for yourself. First perform this simple experiment. Stir together a tablespoonful of stewed tomato and a tablespoonful of milk. What happens? Heat this mixture. What further do you notice? How may you best extract the juice from the tomato? You have noticed the effect of the acid tomato upon the milk. The soda is added to partly counteract this effect. Will you stir the soda into the tomato juice or into the milk? Will you stir the tomato juice into the milk, or the milk into the tomato juice? Will you cook the mixture at all? How long before serving will you mix the two? When will you add the butter and flour?
Laboratory management.—An individual portion of soup may be made with 1⁄2 cup of liquid, but it is better to allow 1 cup when possible to each pupil, or two pupils may work together.
The important point in this soup is to prevent the curdling, so you safeguard the milk at each step.
Croutons may be served with any of these soups.
- Tomatoes 12, medium sized and ripe
- Green pepper 1, finely chopped
- Vinegar 2 cups
- Sugar 3 tablespoonfuls
- Salt 1 tablespoonful
- Clove 2 teaspoonfuls
- Cinnamon 2 teaspoonfuls
- Allspice 2 teaspoonfuls
- Nutmeg 2 teaspoonfuls grated
Method.—Peel tomatoes and slice into a preserving kettle. Add other ingredients and heat to the boiling point. Cook slowly two and one half hours. Pour into preserve jars and seal.
EXERCISES
1. What is the distinction between fruits and vegetables?
2. How does the composition of apples compare with that of carrots?
3. Contrast the nutritive values of celery, potatoes, and old beans.
4. What other foods must be served with potato to make a meal complete?
5. How may we best retain the mineral matter of vegetables in cooking?
6. Is it allowable to cook a vegetable in boiling water and throw away the water?
7. Why must more time be allowed for baking a potato than for boiling?
8. Why more time for an old beet than for a young?
9. Find the cost of potatoes in your locality. Estimate the cost of a dish of mashed potato for five people.
10. Estimate the cost of 100-Calorie portions of several vegetables. See Fig. 36.