The luncheon box most commonly used is of pasteboard or tin. Both these materials have advantages and disadvantages. Bread and cake are prevented from drying out when placed in a tightly covered tin box. On the other hand, food odors are retained and one pronounced odor may permeate all of the foods. But since dry bread is unpalatable, the tin box is considered more satisfactory. It should be kept clean and free from odors, should be emptied of its contents every day, washed (scalded often), and allowed to remain open all night. The collapsible box is the most convenient.
For most lunches, a teaspoon, jelly glass, and in some cases a drinking cup are all the "dishes" needed. The jelly glass may serve for many purposes. Cup custard may be steamed or baked in it, or it makes an admirable mold for an individual steam pudding. Small fruits and fruit sauces may also be carried in jelly glasses.
MENU MAKING FOR THE LUNCHEON BOX.—A luncheon box may be made a source of pleasure to the school child or everyday worker. To bring this about, the foods must be varied on successive days. It is not necessary that each luncheon consist of various foods. Indeed, many kinds of food or foods in great quantity are not desirable for a child who sits quietly at study much of the day or for a person of sedentary occupation. It is both possible and necessary, however,—if the luncheon box is not to become monotonous,—to have different foods for each day of the week. As in any meal, all of the foodstuffs should be represented in the food of a luncheon box.
FOODS FOR THE LUNCHEON BOX.—(1)Sandwiches.—Bread is the basis of almost all box luncheons. Since sandwiches furnish the most convenient way of carrying foods that are to be eaten with bread, they invariably form a part of every luncheon. Because they are used so frequently they should be varied. Different kinds of bread, such as graham, Boston brown, and nut bread, may be used. Variety may be had by serving bread sometimes in the form of muffins or rolls. The slices of bread may be cut thin or thick to suit the appetite of the eater. It is often desirable to leave the crusts on the bread. Butter should be creamed before spreading it on the bread. If the sandwiches are to be cut extremely thin, spread the bread before cutting it into slices. If sandwiches are prepared some time before they are served, they can be kept moist by wrapping in a dry towel, covered with a towel wrung out of hot water.
The fillings for sandwiches offer many variations. They may be divided into two classes, seasoned and sweet.Seasoned fillingsmay include meat, eggs, cheese, vegetables. If meat is used, it may be cut in slices, or chopped and mixed with a sauce. If sliced meat is used, it is well to tear it into pieces. (This applies also to lettuce.) If it is desired to lessen the quantity of meat in a diet, the meat should be chopped, for it has been found that only half as much meat is required when it is chopped and mixed with a dressing. Either Salad Dressing or White Sauce may be combined with meat. A French Dressing made of vegetable oil, lemon juice, and seasonings is better, so far as ease of digestion is concerned, than Cream or "Boiled" Salad Dressing. If oil is not palatable, learn to like it. Any of the seasoned fillings may be mixed with Salad Dressing. Sliced tomatoes spread with Mayonnaise or Cream Salad Dressing, chopped peanuts mixed with salad dressing, sardines or cold chicken with lemon juice and paprika make tasty sandwich fillings.
Sweet fillingsfor sandwiches include: preserved or dried fruits, bananas, nuts. Sandwiches made with a sweet filling are most popular among children. Some of them make good substitutes for cake, and are much more easily digested. The dried fruits such as dates, figs, and prunes, cooked and combined with bread and butter, make excellent foods. The growing child is apt to become anemic. Since prunes contain iron, they should be frequently used in children's diet. Cooked prunes—seeded and flavored with lemon juice—make palatable sandwiches, especially when brown bread is used or a few chopped nuts are added. Breads containing sugar or molasses are most pleasing when used with a sweet filling. Banana sandwiches are much improved by the addition of lemon juice or Salad Dressing. Nuts are often combined with both sweet and seasoned materials; their use gives opportunity for variety. Chopped raisins and nuts may be moistened with grape juice and used as sandwich filling. Chopped dates, apples, and nuts mixed with salad dressing make a pleasing filling. Crushed maple or brown sugar mixed with cream or butter and used with whole wheat bread is a favorite sandwich among children.
(2)Relishes.—Celery, olives, and radishes serve as relishes for the luncheon box. Celery and olives (especially those stuffed with pimentos or nuts) are pleasing as a sandwich filling. Most relishes, however, are more suitable for the luncheon box of a mature person than for that of a child.
(3)Desserts.—Cake is a common constituent of the luncheon box. Not all cakes, however, are suitable for luncheons. For children, only the plainer cakes,i.e.those containing little fat, should be used. Plain cake and cookies, sponge cake, lady fingers, and gingerbread (if not too highly spiced) are also desirable for the school luncheon. Cookies or cakes baked in muffin pans are more suitable for packing than cut pieces of cake.
Most fresh fruits can be easily packed in the luncheon box. As has been mentioned, grapes, the small fruits such as strawberries and raspberries, sliced pineapple, or fruit sauces may be carried in jelly glasses.
Cup custards and simple puddings may be used as desserts. If a child is permitted to have sweets, a little candy may be placed in the luncheon box; it is better for a child to have candy at the end of a luncheon than after school (seeUse of Candy in Diet).
PACKING THE LUNCHEON.—Neatness is an essential in an inviting luncheon box. All foods should be wrapped separately in paraffin paper, and placed neatly in the box. Since some foods crush readily, it is not always possible to place the foods to be eaten first on top, but it is desirable to arrange the foods so that not all of them will have to be removed before beginning to eat the luncheon. The paper napkin should always be placed on top. It is perhaps unnecessary to say that foods should not come in direct contact with newspapers or any printed matter.
Plan menus for five school luncheons, making them as varied as possible. If you carry your luncheon to school, follow these menus in preparing your luncheon box.
Plan [Footnote 115: See Footnote 72.] box luncheons. Make sandwiches and other foods for the luncheon box. Fill one or more luncheon boxes according to plans.
Cake (for Cottage Pudding)Vanilla SauceCocoa
See Lesson XIV for suggestions regarding the preparation of the lesson.
HOME PROJECTS [Footnote 116: See Lesson IX]
SUGGESTIONS FOR HOME WORK.—Bake cake or cookies at least once a week. If eggs are high in price, bake cake without eggs or bake One-egg Cake.
SUGGESTED AIMS: (1) To improve the quality of cake. As suggested in a previous Home Project, score your product, determine the cause of any undesirable quality, and then avoid your error at the next baking.
(2) To compare homemade and baker's cake. Determine the weight and cost of homemade and baker's cake. Compare like kinds of cake,i.e.plain, chocolate, etc. Compute the cost per pound of each. If possible compare the flavor, grain, and texture of each. What are the advantages of homemade over baker's cake?
PASTRY.—Good pastry is: (a) light, (b) flaky or friable, and (c) tender. Thelightnessof pastry is largely dependent upon the temperature of the ingredients. All the materials should be cold, so that the expansion in baking may be as great as possible. In order to keep the ingredients cold and the fats solid, a knife (instead of the fingers) should be used in mixing. It is well to chill pastry by placing it on the ice before rolling out. The lightness of pastry is dependent somewhat upon quick and deft manipulations. A little baking powder also increases the lightness of pastry.
Flakypastry results when the ingredients are mixed so as to form layers. To accomplish this, solid fat is used and it is not cut fine into the dry ingredients, but is left in pieces. Thus, when rolled, there are layers of flour and fat. Pastry is sometimes made by cutting part of the fat into the flour mixture, then moistening and rolling it out; adding the remainder of the fat in small bits, folding and rolling out again.
Friablepastry usually results when oil is used instead of solid fat. The following fats may be used alone or in combination: butter, oleomargarine, lard, vegetable oil or fat, lard substitutes.
To make pastrytenderand not tough, the least possible moisture should be used. The quantity of fat used also determines its tenderness. The more fat used, the less the amount of water required. Less moisture is required when oil rather than solid fat is used. For this reason, many persons can produce more tender pastry by using a cooking oil. The fact that the moisture is decreased when oil is used may also account for the decreased quantity of oil given in the recipe for pastry. Less oil than solid fat will produce the same degree of tenderness, provided less water is used.
PIE WITH THE UNDER CRUST.—Pastry is somewhat difficult of digestion; but a crust that is brittle and easily crumbled is more readily digested than one that is moist and pasty. Pie crust should crumble as finely as a cracker. To prevent moist and pasty pie crust, it is advisable to bake "one crust" pie. If an under crust only is used, it should be baked before adding the filling. The filling should be cooked and sweetened before adding it to the crust.
PLAIN PASTRY (2 crusts)
1 1/2 cupfuls flour 1 teaspoonful baking powder 1/2 teaspoonful salt 1/4 to 1/2 cupful fator1/6 to 1/3 cupful oil Ice water
Mix the dry ingredients, cut in the fat slightly; then add just enough water to hold the ingredients together. Chill; then roll out (one crust at a time).
Pastry should be baked in a hot oven. A pastry shell containing no filling should be baked at 400 degrees F., for 15 to 20 minutes.
Bake a one crust pie on the outside of a pie pan; it should be pricked with a fork before baking.
The pastry trimmings should be utilized. They may be made into tarts or cheese straws.
3 tablespoonfuls flour 3 tablespoonfuls corn-starch 1 cupful sugar 2 cupfuls boiling water 2 egg yolks Juice and grated rind of 1 lemon 1 tablespoonful butter 1/4 teaspoonful salt
2 egg whites 2 tablespoonfuls powdered sugar
Mix the sugar, flour, and corn-starch, add the boiling water. Stir and cook on the back of the range, or over an asbestos mat, for 15 minutes. Add the egg yolks and cook at simmering temperature, until the eggs thicken. Add the remaining ingredients. Cool and place in a baked crust. Cover with a meringue. Bake until the meringue is a light brown,i.e.at 300 degrees F., 10 to 15 minutes.
Note that the lemon is added to the mixture after cooking. Cooking a starchy material with a small amount of acid, dextrinizes the starch. Since dextrin has less thickening power than starch, the starch mixture would become thinner if cooked for some time with lemon.
Flavor 30Tenderness 20Lightness 10Flakiness 10Appearance (color and thickness) 10Filling (flavor and consistency) 20—-Total 100
Why should not the fingers be used to mix the fat with the dry ingredients in pastry making?
Why is it easier to roll out pastry, if it has been chilled after mixing?
Why should a lower crust, when used alone, be baked before adding the filling?
What is the purpose of pricking the lower crust with a fork before baking?
Compare the filling for Lemon Pie with that for Cream Puffs. How do they differ in moisture, method of preparation, and length of time in cooking? Give the reason for these differences.
FromU. S. Department of Agriculture, Bulletin No. 28, tabulate the percentage composition of butter (see Figure 63), oleomargarine, lard, lard substitute, and vegetable oil. What is the price per pound of each?
Which furnishes more fat,—a pound of butter or a pound of lard? If lard, lard substitute, or vegetable oil were substituted for butter in a cake or other quick bread, should the same quantity be used? Explain.
DIGESTION OF PASTRY.—As previously mentioned (seeFrying and Digestion), when fats are heated to a high temperature, they decompose. The products of this decomposition are less readily digested than is fat before it is decomposed. Hence in fried foods, the fat is made somewhat indigestible. Thus it is much better to spread uncooked fat over hot potatoes than to combine the two foods by frying the potatoes.
Fat is the most slowly digested of all foodstuffs. Hence a combination of fat and carbohydrates is more slowly digested than carbohydrate. For this reason, foods consisting of fat and flour such as pastry may remain in the digestive tract for a long time and cause disturbances. Distressing effects are less likely to result, however, when a person's work is out of doors. Since fatty foods remain in the stomach longer than others, they may serve to allay the feeling of hunger which is caused by the contracting of an empty stomach.
PIE WITH THE UPPER CRUST.—In the previous lesson (seePie with Under Crust), it was mentioned that "pasty" pie crust was not readily digested. For this reason, fresh fruit pie may be made with an upper crust only. Such pie should be baked in a pan of granite, glass, or similar material. The fruit is placed in the pie pan, then a half-inch strip of pastry is placed over the rim of the pie pan; the strip is moistened and the crust placed over the top. The strip of pastry and the upper crust are pressed together, then the edges of the latter are trimmed. The upper crust should be cut in several places for the escape of steam.
2 cupfuls rhubarb, cut in small pieces 1 egg 4 tablespoonfuls flour 1 cupful sugar Salt Lemon rind
Mix the sugar, salt, lemon rind, and flour; beat the egg. Add the rhubarb and flour mixture to the egg. Turn into an earthenware dish or a granite pan, and cover with pastry as directed above. Bake until the rhubarb is tender and the crust is brown, i.e. at 425 degrees F., 35 to 45 minutes.
Rhubarb contains such a large percentage of moisture that it is well to use but one crust.
Explain why it is that baked potatoes and butter are more readily digested than fried potatoes.
What is the advantage of using only a top crust for fresh fruit pie?
What is the purpose of egg and flour in Rhubarb Pie? Why is it desirable to use these ingredients with rhubarb?
Why should the flour in Rhubarb Pie be mixed with sugar?
How much water is there in apples and rhubarb (seeU. S. Department ofAgriculture, Bulletin No. 28 and Figure 70)?
TWO CRUSTS.—If both upper and lower crusts are used in making a pie, the lower crust should be placed inside the pan. The filling should be added, the edge of the crust moistened, and the upper crust placed over the pie and pressed around the edges. Then the edges should be trimmed. As was mentioned before, upper crusts should always be cut in several places for the escape of steam.
Sometimes a half-inch strip of pastry is placed around the edge of the under crust before placing the upper crust. This is thought to aid in preventing the escape of the moisture of the filling.
Cut 4 or 5 apples into slices, and for each apple use 2 tablespoonfuls (or more) of sugar. If the apples are not juicy, add from 1/2 to 1 tablespoonful of water for each apple. Flavor with 1 teaspoonful each of lemon juice and rind, 1/4 teaspoonful cinnamon or nutmeg, and 1/8 teaspoonful salt. Line the inside of a pie pan with pastry, pour in the apple mixture. Add bits of butter, and cover with pastry as directed above. Bake until the apples are soft and the crust is brown, i.e. at 425 degrees F., 35 to 45 minutes.
Apple sauce may be used as a filling for a baked crust. Such a pie is sometimes covered with meringue or strips of pastry.
2 cupfuls fruit 1/2 to 1 cupful sugar 3 tablespoonfuls flour
If the fruit is fresh, wash and drain it well. Mix the sugar and flour.Line the inside of a pie pan with pastry, add half of the sugar and flourmixture. Add the fruit, and then the remainder of the sugar and flour.Cover with a top crust according to the directions above.
Explain why pie with only one crust, if properly made, is more desirable than that with two crusts (seePie with Under Crust).
Why should fresh fruit, for fruit pie with two crusts, be well drained after washing?
Give three ways of preventing the juice from boiling over, in a pie with two crusts.
Compare pastry that is made with lard, lard substitutes, vegetable oils and butter, as to taste, appearance, flakiness or friability, and tenderness.
PERFECT FOOD FOR INFANTS.—Nature in her wisdom provides ideal food for the infant,—mother's milk. No perfect substitute has been found for it. It is most unfortunate when a child is denied this food.
It has been found [Footnote 117: See "Feeding the Family," by Mary Swartz Rose, Ph.D., p. 98.] that babies fed with mother's milk are much less likely to contract disease and much more apt to grow to maturity. A mother's milk is adapted to the needs of her child. It agrees with the infant and nourishes it well. A practical advantage of a healthy mother's milk is that it is sterile and of the proper temperature.
MODIFIED MILK.—In case it is necessary to give the infant artificial diet, the greatest care should be taken to provide clean, easily digested food. Cow's milk is the basis of the food generally chosen. The way babies digest cow's milk shows the necessity of changing ormodifyingit to meet the needs of an infant. Cow's milk is modified sometimes by diluting it to make it digest easier and adding other ingredients to it. In order to increase the fuel value of diluted milk, carbohydrate food of some soluble, easily digested kind is added. Sometimes gruel or cereal water is used as one of the constituents of modified milk.
Formulas for modified milk vary with the individual infant. A physician should be consulted regarding the formula for food for a baby.
(a)Utensilsfor measuring and preparing the ingredients of modified milk should be kept very clean. Before using, all glass and metal utensils used for measuring and holding the milk should be covered with cold water, then the water should be heated and allowed to boil for twenty minutes. Just before using rubber nipples, place them in boiling water for a few minutes. After using, they should be rinsed in cold water and then carefully washed inside and out with soap and water. When not in use, nipples should be kept in a clean covered jar or jelly glass. (The jar and cover should be sterilized daily.) After using the milk bottles (have as many bottles as there are feedings a day), rinse them in cold water, and then fill them with water and add a pinch of baking soda. Before filling the bottle with milk, wash with soap and water—using a bottle brush—and then sterilize in boiling water for twenty minutes (as directed above). Bacteria cannot pass through cotton, hence it is used for stoppering the filled milk bottles. It should be clean, however. Paper caps are also used.
(b)Ingredients.—(1)Milk.—The selection of milk for an infant is an important consideration.Clean milkis most essential. Milk is considered clean when it comes from dairy farms where clean milkers work under sanitary conditions, approved by a medical milk commission (seeCare of Milk). Such milk contains few bacteria and is calledcertified milk. This is by far the safest milk for infant diet, but it is expensive. It usually costs almost twice as much as ordinary milk. Milk ispasteurizedcommercially by heating it to 150 degrees F., keeping it at that temperature for about thirty minutes, and then quickly cooling it. While pasteurizing kills most of the disease-producing germs, it does not destroy all the spores (seeMicroorganisms in theSpore Form). The taste of milk is not affected by pasteurizing. Milk issterilized—all germ life destroyed—by heating at 212 degrees F. from one to one and one half hours.
Since the value of milk as an infant food depends upon its cleanliness, it is difficult to state just how old milk may be before it is unsafe for infant feeding. It is safest to use onlyfreshmilk. Bacteria in milk may develop so rapidly that it is unfit to use a few hours after it has been drawn from the cow. Unless milk is certified, it should not be used in summer after it is twenty-four hours old, and in winter, after it is forty-eight hours old.Bottledmilk should be used for infants. According to most plans for modifying milk,whole milkis used.
(2)Sugar.—Several kinds of sugar are used in modified milk. These are:
Milk sugar or lactose.Malt sugar combined with dextrin or dextrimaltose.Granulated sugar or cane sugar.
The advice of a physician should be consulted regarding the kind of sugar best suited to the needs of the particular infant. The first two kinds of sugar can be obtained at a drug store. Granulated sugar is too sweet for general use.
(3)Water or Cereal Water.—If plain water is to be used with milk, it should be boiled before adding to the other ingredients.
In some cases, gruel or cereal water is added. Usually rolled oats or barley flour is the grain used. To prepare either of these use:
4 tablespoonfuls rolled oatsor3 tablespoonfuls barley flour 1 quart cold water
Mix and boil gently until the mixture is reduced to a pint. Then strain through a fine wire strainer or muslin.
[Illustration: Figure 87.—Graduated Measure and Dipper for Measuring theIngredients of Modified Milk.]
(c)Method of Mixing.—Measure the sugar. This ingredient is usually measured in ounces, tablespoonfuls, or teaspoonfuls. (1 1/2 dipperfuls (Figure 87) of milk sugar weigh 1 ounce.) In the graduated measure (Figure 87), measure the water or cereal water for diluting the milk and dissolve the sugar in it. Stir the mixture until the sugar is completely dissolved. Then pour it into the mixing pitcher. Measure the milk (and other ingredients if required) and pour into pitcher. Mix thoroughly. While stirring, turn the proper quantity of food into as many sterilized bottles as are required for a day's feeding. Stopper with cotton or cap. If the milk used is certified, place in a clean refrigerator until used for feeding. If the milk is not certified, it may be pasteurized.
PASTEURIZING MILK AT HOME.—Place the bottles of milk in a wire basket. Then place the basket in a kettle. Pour water in the kettle so that the water is a little higher outside of the bottles than the surface of the milk inside. Heat the water and let it boil for 5 minutes. (Do not begin to count the time until the water reaches the boiling point.) At once cool the milk by allowing a stream of cold water to displace the hot water. Do not allow the cold water to run directly on the hot bottles. When the milk is cooled, place the bottles immediately in a clean refrigerator.
PREPARATION OF MILK BEFORE FEEDING.—At feeding time, milk should be heated to about 98 degrees F. Place the bottle in a pan of warm water. Test the milk for proper temperature. Use the method described in Junket "Custard", for testing the temperature of the milk. Shake the bottle before feeding.
OTHER FOODS GIVEN TO INFANTS.—In addition to modified milk, boiled water should be given to infants. A few other foods—egg yolk or vegetable juices and orange juice—may often be given during the first year. The egg yolk should be soft-cooked. This food supplies iron and increases the Calorific value of the diet. Orange juice (strained through muslin) may be usually given at five or six months of age. It is especially necessary to give orange juice to infants whose milk is pasteurized or sterilized. Its use prevents constipation and scurvy.
ENERGY REQUIREMENT OF AN INFANT.—The energy requirement of an infant is greater than one would suppose. Growth and development are going on at a rapid rate. Like the adult, a baby asleep needs energy to carry on the involuntary activities of its body. When awake such muscular activities as crying, kicking, and throwing of arms require energy. An infant's energy requirement is usually based upon its body weight. According to generally accepted standards [Footnote 118: See "Feeding the Family," by Mary Swartz Rose, Ph.D., p. 103.] an infant's average energy requirement is:
1st to 3d months 50 Calories per pound per day 4th to 6th months 45 Calories per pound per day 7th to 9th months 40 Calories per pound per day 10th to 12th months 35 Calories per pound per day
QUANTITY OF FOOD.—When a baby must be given artificial food entirely or as a supplement to natural food, it is safest and most satisfactory to follow the advice of a physician. It is said, however, that an infant requires an average of 1 1/2 ounces of milk per day for every pound of body weight. After the eighth month, this quantity of milk is usually decreased first to 1 1/3 and then to 1 1/4 ounces for every pound of body weight per day.
The amount of artificial food found satisfactory for the infant during the first few months of its life is usually not sufficient to yield as many Calories as given in the table above. But while the baby is adjusting itself to artificial feeding, it is especially necessary that the stomach be not overtaxed. As the infant develops, the quantity of food can be increased and the deficiency made up later.
Define certified, pasteurized, sterilized, modified, and top milk.
Give reasons for sterilizing utensils used for measuring and holding milk.
In preparing modified milk why is milk diluted? Why is sugar added?
What is the price per quart of certified milk?
Modify cow's milk according to a formula secured from a physician or baby's dispensary. Pasteurize milk.
Baked Sweet Potatoes or Scalloped PotatoesApple Dumpling (made with pastry or biscuit dough)
See Lesson XIV, for suggestions regarding the preparation of the lesson.
HOME PROJECTS [Footnote 119: See Lesson IX.]
SUGGESTIONS FOR HOME WORK.—If pies are served in your home, bake at least one pie a week. In case pies are not used, bake cake in which different quantities of fat are used.
SUGGESTED AIMS: (1) To compare One- and Two-crust Pies. Prepare each kind. Determine the difference in cost, time of preparation, and quality of the crust of each. Which kinds of pies do you consider more successful in regard to quality? Which is cheaper? Which kind meets the approval of other members of your home?
(2) To compare Cake Containing Little and Much Fat. Follow the recipe for One-egg or Plain Cake. Vary the quantity of fat from 1/8 to 1/2 cupful. Make comparisons regarding cost, texture, grain, and flavor. Which amount do you consider most successful from the standpoint of texture, grain, and flavor?
EXPERIMENT 79: MIXTURES FOR FREEZING.—Prepare 2 cupfuls of cracked ice. Place 1 cupful of the cracked ice in each of two bowls. To one bowl of ice add 1/3 cupful of rock salt, and mix thoroughly. Insert thermometers into both bowls and note temperature. What effect does the salt have upon the temperature of the ice?
Allow the ice mixture to stand a few minutes, then observe the difference in the condition of the ice in the two bowls. Besides lowering the temperature, what does the salt do to the ice?
FREEZING WITH ICE AND SALT.—When a solid substance is changed to a liquid, heat is absorbed from surrounding materials. When solid ice liquefies, heat is absorbed from surrounding materials. Salt makes ice liquefy at a lower temperature, thus absorbing more heat from its surroundings. Since foods must be cooled, i.e. heat drawn from them, in order to freeze them, a mixture of ice and salt rather than ice is used in freezing.
If ice and salt surround a tin can containing substances to be frozen, from what is the heat absorbed when the ice is changed to liquid form? Explain why it is that a mixture of ice and salt, rather than ice alone, is used to freeze a dessert.
CONDUCTORS OF HEAT.—In Experiment 2 and in,The Principle of Fireless Cookery, it is shown that some materials are better conductors of heat than others. Which is a better conductor of heat, wood or metal? Explain why it is that most freezers consist of an inner can of metal and an outer bucket of wood. A few freezers have an outside metal bucket. Such freezing devices have been found more satisfactory when heavy paper is tied around the outer metal bucket.
COOLING BY EVAPORATION.—If a few drops of alcohol, ether, or gasoline are poured in the palm of the hand and allowed to evaporate, the hand feels cold. During evaporation, the liquid takes heat from the hand. When any liquid evaporates, heat is absorbed from surrounding materials. Water may be cooled by placing it in a porous jar and hanging it in a breeze.
When there is no ice, this principle of cooling by the rapid evaporation of a liquid may be applied to the cooling of butter and other foods. Wrap butter in an oiled paper and place it in a flower crock or any porous jar. Place the crock in a draft; put a bowl of water beside it. Wrap a wet cloth about the crock and place one end of it in the bowl of water. The continuous evaporation of the moisture keeps the food cool.
PREPARING AND PACKING THE FREEZER.—Scald the can, the cover, and the dasher of the freezer; cool it before the mixture that is to be frozen is placed in it. Adjust the can carefully in the bucket; put in the dasher; pour in the mixture, cover; adjust the crank. Crush the ice for freezing by placing it in a strong bag and pounding it with a wooden mallet. Mix the ice with rock salt in the proportion given below. Then pour the ice and salt mixture around the can of the freezer. The ice and salt mixture should be higher around the can than the level of the mixture inside.
Forfreezingice creams and most ices usethreeparts of cracked ice tooneof rock salt. If ice of coarse grain is desired, use a greater quantity of salt. The less salt in
proportion to ice used, the finer the grain; the process of freezing, however, takes place very slowly when little salt is used.
For mixtures which are frozen by merely packing in ice and salt but are not stirred, such as mousse or parfait, usetwoparts of cracked ice tooneof rock salt.
For packing frozen mixtures after freezing, usefourparts of cracked ice tooneof rock salt.
FREEZING.—If a dessert of fine texture is desired, turn the crank slowly and steadily until the mixture is rather stiff, then turn more rapidly. In making water ices, it is considered advisable by some to turn the crank steadily for 5 minutes, then allow to stand 5 minutes, turn again 5 minutes, and continue until freezing is completed. Do not draw off the salt water while freezing the mixture, unless the salt water stands so high that there is danger of its getting into the can.
When the mixture is frozen, remove the ice and salt around the top of the can; wipe the cover and top; uncover; and remove the dasher. Then stir the frozen mixture thoroughly; place thin paper or paraffin paper over the can; cover; place a cork in the hole of the cover. Drain off all the water which has collected in freezing; repack the freezer with ice and salt mixture in the proportion given above; cover with carpet, blanket, or newspapers; and allow to stand in a cold place several hours.
4 cupfuls water 2 3/4 cupfuls sugar 3 oranges 3 lemons 3 bananas 1/4 teaspoonful salt
Make a sirup of the sugar and water, and then cool it. Extract the juice from the lemons and oranges; crush the peeled and scraped bananas with a wooden potato masher. Mix the fruits and salt immediately with the sirup. Freezeat once. When frozen, remove the dasher and repack as directed above.
A less expensive but more mildly flavored ice may be prepared by using 3 pints of water (instead of 4 cupfuls). When the greater quantity of water is used, 3 1/4 cupfuls (instead of 2 3/4 cupfuls) of sugar should be used.
These recipes for Fruit Ice are modifications of the popular recipe termed"Five Threes."
Explain why it is necessary to scald the can, cover, and dasher of an ice cream freezer (seeCare of Milk).
What harm sometimes results when an ice cream freezer has been carelessly prepared?
Why should not the salt water be drawn from the freezer during freezing (see Experiment 79)?
What is the purpose of placing paper over the can when packing the frozen mixture?
What is the purpose of covering the packed freezer with carpet, blanket, or newspapers (seeThe Principle of Fireless Cookery)?
Why is it well to tie heavy paper around anoutside metalbucket of a freezer?
Why should "Fruit Ice" mixture be frozenat onceafter preparing the fruit?
Heat aids chemical action. Can you explain why acid mixtures are not acted upon by the metal and consequently discolored whenfrozenin a tin or iron can?
Frozen desserts consist of:
(a)Plain Ice Cream.—Cream, sugar, and flavoring. This is sometimes called Philadelphia Ice Cream.
(b)French Ice Cream.—Custard, cream, and flavoring. On the continent, this frozen mixture is called Neapolitan Ice Cream. In this country, three kinds of frozen mixtures served together make up what is termed Neapolitan Ice Cream.
(c)Mousse.—Whipped cream, folded into various sweetened and flavored mixtures, placed in a mold, and packed in ice and salt, but not beaten.
(a)Water Ice.—Fruit juice, water, and sugar.
(b)Sherbet.—Water ice with the addition of dissolved gelatine or beaten whites of eggs.
(c)Frappe.—Water ice of coarse texture.
(d)Granite.—Water ice to which fruit is added after freezing.
Various sweet mixtures.
METHOD OF MIXING FROZEN FOODS.—The sugar of a frozen dessert should always be dissolved. To accomplish this a sirup should be made of the sugar and water (see Experiment 11). For mixtures that contain no eggs, but in which cream or milk is used, the cream or milk may be scalded, and the sugar dissolved in the hot liquid. If eggs are used to thicken ice cream, they should be combined with the sugar and cream and cooked as for a soft custard.
In sherbets, whites of eggs are often used. They are usually beaten stiff, and added uncooked to the mixture. If fruit juice is to be used with milk or cream, the latter should be chilled before adding the fruit. Fruits that are to be frozen with the other ingredients should be crushed thoroughly. Small fruits, or large fruits cut in pieces, are
sometimes added to a dessert after it is frozen, thereby preventing the fruit from freezing and becoming hard. All frozen mixtures should stand several hours before serving, in order to ripen.
1 quart cream 3/4 cupful sugar 1 tablespoonful vanilla
Prepare as directed inMethod of Mixing Frozen Foods.
1 quart cream 1 cupful sugar 2 ounces chocolate 1/3 cupful boiling water Salt 1 teaspoonful vanilla
Scald the cream; add the sugar to it. Prepare the chocolate in the usual way, by cooking it in the boiling water until a smooth paste is formed (seeChocolate). Add the chocolate mixture to the hot cream. Cool, add salt and vanilla, and freeze.
1 quart cream 1 pint milk 3 egg yolks Salt 1 cupful sugar 1 tablespoonful vanilla
Prepare as directed inMethod of Mixing Frozen Foods.
2 cupfuls fruit juice,or3 cupfuls crushed fruit 1 quart cream 2 cupfuls sugar
Prepare and freeze according to theMethod of Mixing Frozen Foods.
For Frozen Fruit or Water Ice, use water instead of cream.
The flavor of most fruits is improved by adding 2 tablespoonfuls of lemon juice to the water mixture.
For Fruit Ice Cream, why is it necessary to chill the cream before adding the fruit juice or crushed fruit (see Experiment 61)?
Why is it necessary to crush the fruit for frozen fruit mixture?
How much sugar would be required to sweeten one and one half quarts of custard, according to the recipe for Soft Custard? Compare this with the quantity of sugar used for French Ice Cream. How do extremely cold beverages affect the sense of taste? From this, account for the difference in the quantity of sugar used in frozen and in cold desserts. Also compare the quantity of sugar and vanilla used in Chocolate Ice Cream and Chocolate Beverage. Account for the difference.
Approximately how much ice is required to freeze and pack one quart of IceCream? What is the cost of ice per hundred pounds?
How many persons does one quart of ice cream serve?
SELECTION OF FOOD FOR CHILDREN (2 to 12 years).—Although solid food is included in the diet of a child after the first year, the baby is by no means ready for the food of adults. Childhood differs essentially from maturity in that it is a period of growth. In proportion to weight a child is much more active than an adult. A child has not the reserve power of a grown-up person. His organs of digestion and assimilation are delicate. Because the activities and needs of the child differ greatly from those of the adult, diet suitable for the adult is not adapted to the child. A consideration of foods for young children follows:
(1)Milk.—Since milk is the food provided for young animals, it should be used generously all through childhood. The nutritive value of milk is high in proportion to the effort required to digest and assimilate it. The average child with good digestion should take from one and one half pints to one quart daily until the tenth year. In this amount is included not only the milk that is used as a beverage, but the milk served with cereals and vegetables and that used in soups, custards, blanc mange, rice and bread puddings, and other easily digested desserts.
(2)Cereals and Breads.—Well-cooked cereals are among the essential foods of childhood. "Ready-to-serve" breakfast cereals are undesirable as staples for young children. Cereals should becookedfromonetothree hours. For very young children (under eighteen months) all cereals must be strained. For older children, unstrained cereals may be used, provided they are thoroughly cooked. Frequent use of the whole grains, as rolled oats and wheat, is recommended. These cereals contain more protein and ash than the finer cereals and hence may be better body-builders, but they also contain much bran. Usually the latter does not prove irritating if thoroughly cooked. But if these coarse cereals do cause irritation they should either be strained or the cereals containing less bran, as cream of wheat, farina, and arrowroot, should be used. Cereals should be served with milk or cream, but with no sugar or sirup or not more than one teaspoonful to a serving.
Carefully made toast, "zwieback," and stale bread may be given to young children. On account of the difficulty in digesting fresh breads, they are excluded from children's diet.
(3)Eggsare especially good foods for children, provided they are fresh and properly cooked. They should be cooked in some way which leaves them soft such as soft-cooking or poaching. Only soft-cooked egg yolks should be given to children under three years. One whole egg per day may be included in the diet of older children.
(4)Broth and Meat.—There is some difference of opinion regarding the use of meat in children's diet. Some authorities advise beef broth and the more easily digested meats for young children. Others say that if a generous amount of eggs and milk is included in children's diet, it is well not to give them meat before eight years. In the diets for children from two to eight years, neither broth nor meat is included. It is possible to obtain sufficient protein from milk and eggs. Doubtless, as with adults, most young children would be benefited by much less meat than is generally given them or by none at all. If meat is given to young children, it should be scraped (see Experiment 50) and pan-broiled (seePan-Broiling), as it is somewhat difficult to masticate.
(5)Fresh Vegetablesshould be included in children's diet. For very young children select mild vegetables such as spinach, asparagus tips, string beans, and peas. Cook until very soft and press through a sieve or mash. Later, such cooked vegetables as potatoes (baked or mashed), beets, carrots, cauliflower, and squash may be added. No uncooked vegetables should be given to young children.
(6)Fruits and Sugar.—Fruits are especially valuable for children. Care should be taken, however, in selecting fruits. It is said that until a child is five years old only cooked fruits and the juice of fresh fruits should be given. For very young children the juice of orange or the pulp of cooked prunes should be given daily, because they contain valuable nutrients and possess laxative properties. For older children the cooked food fruits (seeKinds of Fruits) such as dates, figs, and raisins (without seeds), and bananas (baked) are desirable. Apples, peaches, and apricots, baked or made into sauces, are also suggested.
Fruits should be cooked with little or no sugar. Sweets in the form of sweet fruits rather than sugar and candy should be given to children under six years. After six years, very little candy or sweet chocolate may be given at the end of a meal, not between meals. It is a mistake to give children candy just because they want it (seeThe Use of Candy in Diet.)
(7)Desserts.—Fruits selected and prepared as given in the previous section, very plain cakes—sponge cake and those containing little fat—and easily digested desserts made of eggs, milk, cereals, etc., are the only desserts suitable for young children.
(8)Water and Other Beverages.—"Pure" water in generous quantities is needed for children. Water and milk are the only beverages (if milk can be considered a beverage) that should be given to children under six years. After that age, cocoa made with much milk may be given, but not tea, coffee, or any carbonated drinks.
THE IMPORTANCE OF PROPER DIET FOR CHILDREN cannot be over-emphasized. It is a child's right to be "hardy." Good food in proper quantity given at the right time is essential for the sure and steady growth of the body. The child's future health, usefulness, and happiness depend much upon the nourishment he receives. If insufficient food, or food lacking in foodstuffs for growth, is given to children, a wasting away of brain cells and muscle may take place and stunted growth will result. The additional care in preparing special menus for children is an effort well worth making; its compensation is inestimable. If from babyhood a child is given his own special diet, it is possible to satisfy him at the table with food that differs from that of the rest of the family. Habits of eating plain food should be established in childhood. Mrs. Richards says: "Habit rather than instinct guides civilized man in the choice of food." Likes or dislikes for food should not be discussed in the presence of children. Such discussions may establish distaste for a food of decided nutritive value.
Regularity in feedingchildren is most important. There should be no lunches between meals. It is important also that a child be taught tomasticatefood thoroughly.
ENERGY REQUIREMENTS OF CHILDREN OF DIFFERENT AGES.—It is difficult to write definitely regarding the quantity of food that should be given to children. As with adults, some children require more than others. The personal factor enters largely into this question. In Lesson CXXIV the energy requirements of children of different ages are given (seeRelation of Age to Daily Energy Requirement). As stated there, these tables indicate the energy requirement of children of normal size, development, and activity. Note that in the menus given below the Calories derived from protein are approximately one seventh of the total Calories (seeDaily Protein Requirement).
The following menus [Footnote 120: Prepared by Mary Swartz Rose, Ph.D., Assistant Professor of Nutrition, School of Household Arts, Teachers College, Columbia University (see Teachers College Bulletin, "The Feeding of Young Children," pp. 6-9).] for children from two to twelve years were prepared for average children of moderate activity in a family of limited income.
Child 2-4 Years Old
Breakfast: 7:30 A.M. Oatmeal Mush 0.8 ounce dry cerealMilk 1 1/2 cupfulsStale Bread 1 sliceOrange Juice 4 tablespoonfuls
Lunch: 11 A.M. Milk 1 cupfulStale Bread 1 sliceButter 1 teaspoonful
Dinner: 1 P.M. Baked Potato 1Boiled Onion (Mashed) 1Bread and Butter 1 sliceMilk to Drink 1 cupfulBaked Apple 1
Supper: 5:30 P.M. Boiled Rice 1 cupfulMilk 3/4 cupfulBread and Butter 1 slice
Fuel Value, 1313 Calories; Calories derived from protein, 191.2.
Substitutes or Additions:
For Rolled Oats or Rice: Other cereals, such as rolled wheat, wheaten grits, farina, hominy, and corn-meal.
For Orange Juice and Baked Apple: Prune pulp or apple sauce.
For Onions: Spinach, strained peas, stewed celery, carrots, or cauliflower tips.
An egg may be added every day, and should be included at least two or three times a week.
These changes will alter the cost somewhat.
Child 4-8 Years Old
Breakfast: Oatmeal 1 1/2 ounces dry cerealTop Milk 4 ouncesStewed Prunes 4 or 5Toast 1 sliceMilk to Drink 6 ounces
Dinner: Pea Soup 1 cupfulCroutons 1 slice breadBoiled Onions 2 smallBaked Potato 1 largeMolasses Cookies 2
Supper: Cream Toast 2 slices breadRice Pudding withMilk and Sugar 1 cupfulMilk to Drink 5 ounces
Fuel Value, 1892 Calories; Calories derived from protein, 261.6.
Substitutes or Additions:
For Rolled Oats: Other cereals, as suggested on previous page.
For Onions and Peas: Strained dried beans; other vegetables carefully cooked; fresh lettuce.
For Prunes: Fresh ripe apples, baked bananas, other mild fruits well cooked.
For Rice Pudding: Junkets, custards, blanc manges, bread puddings, and other very simple desserts.
For Cookies: Gingerbread, sponge cake, or very plain cookies.
Child 8-12 Years Old
Breakfast: Oatmeal Mush 1 1/2 ounces dry cerealTop Milk 6 ouncesStewed Prunes 6 or 7Toast 2 slicesMilk to Drink 6 ounces
Luncheon: Pea Soup 1 cupfulBoiled Onions 2 smallBaked Potato 1 largeBread and Butter 2 slices breadMolasses Cookies 3 cookies
Dinner: Baked Haddock small serving (2 ounces)Creamed Hashed Potato 3/4 cupfulSpinach 1/2 cupfulBread and Butter 2 slicesRice Pudding—Milkand Sugar 1 cupful
Fuel Value, 2420 Calories; Calories derived from protein, 345.6.
Substitutes or Additions:
For Rolled Oats: Other cereals thoroughly cooked.
For Haddock: Rare beefsteak, roast beef, or mutton chops; other fish, especially white varieties.
For Prunes: Any mild ripe fruit uncooked or cooked.
For Onions: String beans, stewed celery, beets, squash. Peas or Spinach:Turnips or cauliflower.
Suggestive Dietary for Child who will not Drink Milk, Age 5 Years
(1 quart milk concealed in the menu.)
Breakfast:7 A.M. Oatmeal 1/4 cup cereal cooked in 1 cupfulmilkCreamy Egg on Toast 1 egg yolk with 1/2 slice breadand 1/4 cupful milkCocoa 1 teaspoonful cocoa and 1/4 cupfulmilk
10 A.M. "Zwieback" and Cream 1 piece "zwieback" and 1tablespoonful cream
1:30 P.M. Spinach Soup 4 ouncesBaked Potato with 1 potato and 2 tablespoonfulsCream creamBread and Butter 1 sliceCaramel Junket 1 1/2 cupfuls
5:30 P.M. Rice and Prunes 2 tablespoonfuls rice cooked in1/2 cupful milk, and 5 prunes"Zwieback" 1 slice
Total Calories, 1431; Calories from protein, 207.6.
Give at least three reasons why young children should have different food from adults.
Why are not ready-to-serve cereals suitable staple foods for young children?
What are the advantages of using whole grains for children's food?
Why not serve sugar with breakfast cereals for children?
Why is not meat a desirable food for most young children?
Why are fresh vegetables and fruits such necessary foods for children?
Plan [Footnote 121: See Footnote 72.] a day's feeding for a child of five years, meeting the total energy and the protein requirements. Prepare these foods.
Creamed VegetableApricot DaintyCoffee
See Lesson XIV for suggestions regarding the preparation of the lesson.
HOME PROJECTS [Footnote 122: See Lesson IX.]
SUGGESTIONS FOR HOME WORK.—Plan a week's diet for a small sister, brother, or other child in whom you are interested. (Follow suggestions given in Lesson CLXII.) Calculate the total Calorific value and Calories derived from protein. Does your menu consist of foods which furnish the proper Calorific value and Calories derived from protein?
SUPPOSED AIMS: (1) If your menus do not conform to the requirements, to change them so as to meet the requirements of the young child.
(2) If possible, to arrange to have your menus prepared and fed to the child, assisting as much as possible in the preparation of the food and in the feeding of the child.
WHY FOODS SPOIL.—Most foods spoil or change readily,—fruits decay, milk sours, butter becomes rancid, and meat putrefies. Knowledge concerning the spoiling of foods makes it possible for the housekeeper to preserve foods from one season to another; it gives her the assurance that her preserved fruit will "keep."
The decay of foods is due largely to the existence of minute vegetable organisms or microorganisms. These microorganisms are molds, yeasts, and bacteria. The molds (see Figure 88) are visible to the naked eye, the yeasts (see Figure 86) and bacteria (see Figure 89) are microscopic in size. These plants exist everywhere, and in everything (except those things in which the organisms have been destroyed and prevented from reentering),—in the air, in and on foods, and all over our bodies. Like all plants, these organisms require warmth, moisture, and food for their most rapid growth. Oxygen is necessary for the growth of some of these plants.
Many foods constitute nourishment for these organisms. It is because these plants exist in foods and live upon them that changes in foods result. The mold on bread and fruit, the odor from decaying meat and eggs, the liquefaction of decayed eggs, and the gas from fermenting canned fruit are caused by microorganisms existing and growing in these foods. The following experiments show the growth of molds on food and other materials:
EXPERIMENT 80: EFFECT OF AIR, LIGHT, AND DRYING UPON THE GROWTH OF MOLDS. —Place a piece of bread on a saucer. Allow it to remain uncovered, in a light place, at room temperature, for several days. Examine. What is the condition (moist or dry) of the bread? Have molds grown upon the bread?
[Illustration: From Household Bacteriology, by Buchanan. FIGURE 88.—SOMESPECIES OF MOLDS.]
EXPERIMENT 81: EFFECT OF MOISTURE AND LIGHT UPON THE GROWTH OF MOLDS.— Sprinkle a thick piece of bread with water, place it on a saucer, and cover with a jelly glass or any glass dish. Leave in a light place at room temperature for several days. Examine. Is the bread moist or dry? Have molds grown upon the bread?
From the results of Experiments 80 and 81 what would you say has caused the molds to grow? What conclusion can you draw
from this concerning the growth of molds upon foods in damp and dry places and in damp and dry weather? How should bread be stored in dry weather? In damp weather? Give the reason for storing Dried Bread Crumbs as directed in Lesson L.
EXPERIMENT 82: EFFECT OF MOISTURE AND DARKNESS UPON THE GROWTH OF MOLDS.— Repeat Experiment 81, except the method of covering. Cover with an earthen dish so that the light is excluded. Let it remain at room temperature for the same length of time as given in Experiment 81. Have molds grown? How does the growth compare in quantity with that of Experiment 81?
EXPERIMENT 83: EFFECT OF MOISTURE AND LOW TEMPERATURES UPON THE GROWTH OF MOLDS.—Repeat Experiment 81, but place the bread on the lower shelf of the refrigerator. After several days, examine. Have molds grown? How do they compare in quantity with that of Experiment 81? What conclusion can you draw from this concerning the temperature at which food liable to mold should be kept?
EXPERIMENT 84: GROWTH OF MOLDS UPON CUT FRUIT.—Place pieces of apple, banana, lemon, or other fruits on separate saucers and cover each with a glass dish. Place some lemon or other fruit juice in a test tube and allow it to stand. After two days examine. Have molds grown on all the fruits? Do you notice any difference in the quantity of the molds on the different fruits? Have molds grown on the fruit juice?
EXPERIMENT 85: GROWTH OF MOLDS UPON WHOLE FRUITS.—Place whole fruits, such as apples and lemons, on saucers and cover with glass. After two days examine. Have molds grown upon the whole fruits? If so, how do the molds compare in quantity to those growing on cut fruit? Account for this difference. Apply the results of Experiments 84 and 85 to the "keeping" of fresh fruits.
EXPERIMENT 86: GROWTH OF MOLDS ON OTHER FOODS.—Place a piece of cheese and a piece of meat on separate saucers and cover each with a glass dish. After two days examine. Have molds grown upon these foods? Account for the growth of molds upon these foods when no moisture was added to them. Devise a method for keeping cheese free from mold. Give the reasons for your method.
EXPERIMENT 87: GROWTH OF MOLD UPON WOOD.—Soak a bit of wood in water for at least 15 minutes. Cover it with an earthen dish and let it stand at room temperature for several days. Examine. Have molds grown upon the wood? What has caused the molds to grow upon the wood? From this give directions for the care of the wooden part of the dasher of an ice cream freezer. Draw conclusions concerning the care of pastry and bread boards and butter paddles after scrubbing. Draw conclusions concerning the scrubbing, drying, and airing of wooden floors.
EXPERIMENT 88: GROWTH OF MOLDS UPON CLOTH.—Sprinkle a bit of cloth with water. Cover with an earthen dish. Let stand a few days at room temperature. Examine. Have molds (mildew) grown upon the cloth? What caused the molds to grow? From this draw a conclusion concerning the care of washed clothes, wet dish-cloths, towels, and wash-cloths.
EXPERIMENT 89: CONTAMINATION OF FRESH FOOD BY MEANS OF MOLDY FOOD.—Dip a piece of bread in water and place it on a saucer. With a knitting needle, place bits of mold at several points on the surface of the bread. Cover with a glass dish. After several days examine. At what points on the bread have the molds started to grow? What conclusion can you draw from this concerning the placing of moldy food with fresh food? When fruit is falling to the ground, tell how an orchard should be cared for. Explain.
The following experiments show the growth of bacteria on food:
EXPERIMENT 90: GROWTH OF BACTERIA.—Into test tubes put one of the following foods: (1) bit of uncooked meat; (2) small quantity of egg; (3) piece of bread; (4) crushed peas or beans; (5) sugar or syrup. Add a little water to each tube. Set aside in a warm place. After several days, examine. What change in appearance do you note? What has caused the foods to spoil?
EXPERIMENT 91: EFFECT OF BOILING ON THE GROWTH OF BACTERIA.—Place a little chopped meat in two test tubes. Add lukewarm water to each. Boil the contents of one of the tubes for several minutes. Set both aside. After 24 hours, examine. What difference is there in the condition of the meat in each tube? Explain this difference. From the result of this Experiment draw conclusions regarding the boiling of food to prevent spoiling.
EXPERIMENT 92: EFFECT OF PRESERVATIVES ON THE GROWTH OF BACTERIA.—Beat slightly an egg white. Add to it 1/2 cupful of water. Pour a little of the diluted egg white into four test tubes. To three of the test tubes add one of the following: (1) salt; (2) sugar; (3) vinegar. Put all of the tubes in a warm place. After several days, examine. What is the condition of the egg white in each tube? Explain. Draw inferences regarding the use of "safe" preservatives to prevent foods from spoiling.
THE PRINCIPLES OF PRESERVING FOOD.—Food may be preserved by opposing the growth of microorganisms or by destroying them. Low temperatures, certain preservatives, and drying destroy microorganisms or retard their growth.
[Illustration: From Household Bacteriology, by Buchanan
FIGURE 89.-THE FOUR TYPES OF BACTERIA. A, cocci; B, bacilli; C, spirilla;D, branched filamentous organism.]
Drying is effective in preserving such foods as fruits, certain vegetables, fish, and meats. The drying of fruit and vegetables may be done in the home. This process of food preservation is often advisable when there is an excessive supply of fruit or vegetables in the orchard or garden.
Substances known aspreservativesare used in food preservation. Some of these are harmless, as sugar, salt, vinegar, and spices. Others are harmful, as formaldehyde, boric, salicylic, benzoic, and sulphurous acids, with their related compounds. Saltpeter and smoke are also preservatives. There is some doubt concerning the harmlessness of these latter preserving agents. Foods preserved with harmful materials should never be used. Good food materials can be preserved without the use of harmful preservatives.
The destruction of microorganisms byheatis the basic principle of preserving much food, especially fruit and vegetables. In order to preserve fruits it is necessary toprocessthem,i.e.to apply heat in such a way as to insure preservation and secure the maximum of good quality. To do this, the fruit must be cooked well, packed in cans which have been boiled, and sealed to exclude the air from them. It is necessary, also, to sterilize all utensils which come in contact with the foods in the processes of cooking and sealing.
If canned fruits do not "keep," some microorganisms either in the fruit, on the can, or on the utensils used in canning, have not been destroyed, or the can has not been securely sealed. Slight flaws in the can or rubbers which were not detected at the time of sealing may cause the spoiling of carefully canned fruit. In the preservation of fruit, every effort should be made to secure sound fruit, perfect jars, and good rubbers, and to have the fruit and utensils perfectly processed, and the jars securely sealed. Failure to accomplish these ends may result in much loss of materials and time.