Keeping Cooked Food Safe
38. Although, as has been explained, the selection and preparation of foods require much consideration from the housewife who desires to get good results in cookery, there is still one thing to which she must give attention if she would keep down the cost of living, and that is the care of food. Unless food is properly taken care of before it is cooked, as well as after it is cooked--that is, the left-overs--considerable loss is liable to result through its spoiling or decaying. Both uncooked and cooked food may be kept wholesome in several ways, but before these are discussed it may be well to look into the causes of spoiling. With these causes understood, the methods of caring for foods will be better appreciated, and the results in buying, storing, and handling foods will be more satisfactory.
39. To come to a knowledge of why foods spoil, it will be well to note that nature abounds in micro-organisms, or living things so minute as to be invisible to the naked eye. These micro-organisms are known to science as microbes and germs, and they are comprised of bacteria, yeasts, and molds, a knowledge of which is of the utmost importance to the physician and the farmer, as well as the housewife. Just in what ways these are beneficial to the farmer and the physician is beyond the scope of the subject of cookery, but in the household their influence is felt in three ways: They are the cause of the decay and spoiling of foods; they are of value in the preparation of certain foods; and they are the cause of contagious diseases. It will thus be seen that while some microbes are undesirable, others exert a beneficial action.
40. It is only within comparatively recent years that the action of micro-organisms has been understood. It is now definitely known that these minute living things seize every possible chance to attack articles of food and produce the changes known as fermentation, putrefaction, souring, and decay. Micro-organisms that cause fermentation are necessary in bread making and vinegar making, but they are destructive to other foods, as, for example, those which are canned or preserved. Organisms that cause putrefaction are needed in the making of sauer kraut, salt rising bread, and cheese. Molds also help to make cheese, but neither these nor putrefactive organisms are desirable for foods other than those mentioned. It should be remembered, however, that even those foods which require micro-organisms in their making are constantly in danger of the attacks of these small living things, for unless something is done to retard their growth they will cause food to sour or decay and thus become unfit for consumption.
Some foods, of course, withstand the attacks of micro-organisms for longer periods of time than others. For example, most fruits that are protected by an unbroken skin will, under the right conditions, keep for long periods of time, but berries, on account of having less protective covering, spoil much more quickly. Likewise, vegetables without skins decay faster than those with skins, because they have no protective covering and contain more water, in which, as is definitely known, most micro-organisms thrive.
41. If food is to be kept from decaying, the housewife must endeavor to prevent the growth of micro-organisms, and she can best accomplish this if she is familiar with the ways in which they work. It is for this reason that, whether she possesses a scientific knowledge of bacteria or not, an understanding of some practical facts concerning why food spoils and how to keep it from decaying is imperative. In this part of cookery, as in every other phase, it is the reason why things should be done that makes all that relates to the cooking of food so interesting. In all parts of the work there are scientific facts underlying the processes, and the more the housewife learns about these, the more she can exercise the art of cookery, which, like all other arts, depends on scientific principles.
METHODS OF CARE
42. As has been pointed out, it is not the mere presence of micro-organisms that causes the spoiling of food, but their constant growth. Therefore, to keep milk from souring, meat from spoiling, bread from molding, canned fruit from fermenting, and so on, it is necessary to know what will prevent the growth of these minute organisms. Different foods require different treatment. Some foods must be kept very cold, some must be heated or cooked, others must be dried, and to others must be added preservatives. An unwarrantable prejudice has been raised in the minds of many persons against the use of preservatives, but this is due to the fact that the term is not properly understood. In this use, it means anything that helps to preserve or keep safe the food to which it is added. Sugar, salt, spices, and vinegar are all preservatives, and are added to food as much for the purpose of preserving it as for seasoning it.
CANNING AND DRYING OF FOODS
43. Among the common methods of caring for foods that are to be used at a future time are canning and drying. CANNING, which is discussed fully in another Section, consists in preserving sterile foods in sealed cans or jars. The aim in canning is to prevent the growth of micro-organisms, and to do this the process known as sterilizing--that is, the destroying of bacteria and other micro-organisms by means of heat--is resorted to. Canning theories are different now from what they were in former times. For example, housewives formerly made heavy, rich preserves of available fruits because it was thought that sugar must be used in large quantities in order to keep or prevent them from spoiling. While it is true that the sugar assisted, science has since proved that sterilizing is what must be done, so that now only the sugar desired for sweetening need be used.
44. The other method of keeping food, namely, DRYING, depends for its success on the fact that such micro-organisms as bacteria cannot grow unless they have a considerable quantity of moisture or water. Molds grow on cheese, bread, damp cloth or paper, or articles that contain only a small amount of moisture, but bacteria need from 20 to 30 per cent. of water in food in order to grow and multiply. This explains why in high altitudes and dry climates foods keep for a long time without artificial means of preservation. It also explains why the old-fashioned housekeeper dried fruits and why the preservation of certain meats is accomplished by the combined methods of smoking and drying, the creosote of the smoke given off from the wood used in this process acting as a preservative. All the grains, which are very dry, keep for long periods of time, even centuries, if they are protected from the moisture of the air. Peas, beans, and lentils, as well as dried biscuits and crackers, are all examples of how well food will keep when little or no moisture is present.
KEEPING FOODS WITH ICE
45. Although, as has just been pointed out, moisture is required for the growth of some micro-organisms, both moisture and warmth are necessary for the growth of most of the organisms that cause molding, putrefaction, and fermentation. It is definitely known, also, that in winter or in cold climates food can be kept for long periods of time without any apparent change; in fact, the lower the temperature the less likely are foods to spoil, although freezing renders many of them unfit for use. These facts are what led up to the scientific truth that keeping foods dry and at a low temperature is an effective and convenient method of preventing them from spoiling and to the invention of the refrigerator and other devices and methods for the cold storage of foods.
46. THE REFRIGERATOR.
--For home use, the refrigerator offers the most convenient means of keeping foods in good condition. As is well known, it is a device that, by means of air cooled by the melting of ice or in some other manner, keeps food at a temperature near the freezing point. All refrigerators are constructed in a similar manner, having two or more layers of wood between which is placed an insulating material, such as cork, asbestos, or mineral wool. The food compartments are lined with tile, zinc, or other rust-proof material, and the ice compartment is usually lined with rust-proof metal, so as to be water-tight and unbreakable. Any refrigerator may be made to serve the purpose of preserving food effectively if it is well constructed, the ice chamber kept as full of ice as possible, and the housewife knows how to arrange the foods in the food chambers to the best advantage.
The construction and use of refrigerators are based on the well-known scientific fact that air expands and rises when it becomes warm. This can be proved by testing the air near the ceiling of a room, for no matter how warm it is near the floor it will always be warmer above. The same thing occurs in a refrigerator. As air comes in contact with the ice, it is cooled and falls, and the warm air is forced up. Thus the air is kept in constant motion, or circulation.
47. Many refrigerators are built with the ice compartment on one side, as in the refrigerator illustrated in Fig. 12. In such refrigerators, there is usually a small food compartment directly under the ice chamber, and this is the coldest place in the refrigerator. Here should be stored the foods that need special care or that absorb odors and flavors readily, such as milk, butter, cream, meat, etc., because at this place the air, which circulates in the manner indicated by the arrow, is the purest. The foods that give off odors strong enough to taint others should be kept on the upper shelves of the refrigerator, through which the current of air passes last before being freed from odors by passing over the ice.
48. In Fig. 13 is shown a type of refrigerator in which the ice chamber, or compartment, extends across the entire top. This type is so built as to produce on each side a current of air that passes down from the ice at the center and back up to the ice near the outside walls, as shown by the arrows. A different arrangement is required for the food in this kind of refrigerator, those which give off odors and flavors being placed in the bottom compartment, or farthest from the ice, and those which take up odors and flavors, on the top shelf, or nearest the ice. A careful study of both Figs. 12 and 13 is advised, for they show the best arrangement of food in each type of refrigerator.
49. CARE OF FOOD IN REFRIGERATOR.--The proper placing of foods in a refrigerator is extremely important, but certain precautions should be taken with regard to the food itself. Cooked foods should never be placed in the refrigerator without first allowing them to cool, for the steam given off when a dish of hot food comes in contact with the cold air makes the refrigerator damp and causes an undue waste of ice by warming the air. All dishes containing food should be wiped dry and carefully covered before they are placed in the refrigerator, so as to keep unnecessary moisture out of it. As butter and milk are likely to become contaminated with odors given off by other foods, they should be properly protected if there is not a separate compartment in which to keep them. The milk bottles should always be closed and the butter carefully wrapped or put in a covered receptacle. Onions, cabbage, and other foods with strong odors, when placed in the refrigerator, should be kept in tightly closed jars or dishes, so that the odors will not escape. Before fresh fruits and perishable vegetables--that is, vegetables that decay easily--are put into the refrigerator, they should be carefully looked over and all decayed portions removed from them. No food should be placed in the ice chamber, because this will cause the ice to melt unnecessarily.
50. CARE OF THE REFRIGERATOR.--It is essential that all parts of the refrigerator be kept scrupulously clean and as dry as possible. To accomplish this, nothing should be allowed to spoil in it, and anything spilled in the refrigerator should be cleaned out immediately. The foods that are left over should be carefully inspected every day, and anything not likely to be used within a day or so should be disposed of. At least once a week the food should be removed from all compartments, the racks taken out, the drain pipe disconnected, and each part thoroughly washed, rinsed with boiling water, and dried. The inside of the refrigerator should likewise be washed, rinsed, and wiped dry, after which the drain pipe should be connected, the shelves put back in place, and the food replaced.
The ice chamber of the refrigerator should also be cleaned frequently, the best time to do this being when the ice has melted enough to be lifted out conveniently. To prevent the ice from melting rapidly when it is out of the refrigerator, it may be wrapped in paper or a piece of old blanket, but this covering must be removed when the ice is replaced in the chamber, in order to allow the ice to melt in the refrigerator. Otherwise, it would be impossible to chill the refrigerator properly, the temperature remaining the same as that outside, for it is as the ice gradually melts that the air in the refrigerator becomes cool. Of course, every effort should be made to keep the ice from wasting. Therefore, while the refrigerator should be kept in a convenient place, it should not be exposed to too great heat; also, the doors should be kept tightly closed, and, as has already been explained, hot foods should not be put in until they are sufficiently cooled. Attention must be given to the care of the refrigerator, for only when it is clean and dry can the growth of bacteria that attack foods be prevented.
KEEPING FOODS WITHOUT ICE
51. While a refrigerator simplifies the preserving of cooked foods and those subject to quick decay, there are many communities in which it is not possible to procure ice conveniently, thus making it necessary to adopt some other means of keeping food. Then, too, there are generally quantities of foods, such as winter vegetables, apples, etc., that cannot be stored in a refrigerator, but must be taken care of properly. In such cases, the method of storing depends to a certain extent on conditions. On many farms there are spring houses in which foods may be stored in order to keep them cool during very warm weather; but in the majority of homes, the cellar, on account of its being cool, is utilized for the storage of large quantities of food and even for keeping the more perishable foods when ice cannot be obtained.
52. STORING FOODS IN CELLARS.
--In order that a cellar may furnish a safe place for keeping food, it must be well built and properly cared for. If it is dug in wet ground and is not well drained, it will become musty and damp, and fruits and vegetables stored in it will be attacked by mold. A small part of the cellar should be without a floor, as many winter vegetables seem to keep better when placed on dry ground, but the remainder should have a flooring of either well-matched boards or cement that can be kept clean and dry. Ventilation must also be supplied; otherwise, odors will be retained that will taint the food kept in the cellar. To allow the passage of air and light from the outside and thus secure proper ventilation, the cellar should be provided with windows. These will also assist very much in the cleaning and airing of the cellar, processes that should never be overlooked if good results are desired. In addition to the cleaning of the cellar, constant attention should be given to the foods kept there. Foods that have spoiled or are beginning to spoil should be disposed of quickly, for decayed food that is not removed from the cellar will affect the conditions for keeping other foods and may be injurious to the health of the family.
53. All foods likely to be contaminated by dust and flies in the cellar must be carefully covered. A screened frame fastened to the wall with brackets, like the one shown in Fig. 14, is excellent for this purpose, because it prevents the attack of vermin and permits of ventilation. If canned goods are to be stored, a cellar cupboard like that shown in Fig. 15 is a very good place in which to keep them. Separate bins should, if possible, be provided for fruits, potatoes, and other winter vegetables, and, as shown in Fig. 16, such bins should be so built as to allow air to pass through them.
54. WINDOW BOXES.
--The woman who lives in an apartment where there is no cellar and who does not wish to keep ice in the refrigerator through the winter will find a window box a very good device in which to keep food. Such a box is also a convenience for the woman who has a cellar, but wishes to save steps. A box of this kind is built to fit a kitchen or a pantry window, and is placed outside of the window, so that the opening comes toward the room. Such an arrangement, which is illustrated in Fig. 17, will make the contents of the box easily accessible when the window is raised. A box for this purpose may be made of wood or galvanized iron, and it is usually supported by suitable brackets. Its capacity may be increased by building a shelf in it half way to the top, and provided it is made of wood, it can be more easily cleaned if it is lined with table oilcloth.
STORING OF NON-PERISHABLE FOODS
55. It may seem unnecessary to give much attention to the storing of foods that do not spoil easily, but there are good reasons why such foods require careful storage. They should be properly cared for to prevent the loss of flavor by exposure to the air, to prevent the absorption of moisture, which produces a favorable opportunity for the growth of molds, and to prevent the attacks of insects and vermin. The best way in which to care for such foods is to store them in tightly closed vessels. Earthenware and glass jars, lard pails, coffee and cocoa cans, all carefully cleaned and having lids to fit, prove to be very satisfactory receptacles for such purposes.
56. Unless coffee, tea, cocoa, spices, and prepared cereals are bought in cans or moisture-proof containers, they should be emptied from the original packages and placed in jars that can be tightly closed, so that they will not deteriorate by being exposed to the air or moisture. For convenience and economy, these jars or cans should be labeled. Sugar and salt absorb moisture and form lumps when exposed to the air, and they, too, should be properly kept. A tin receptacle is the best kind for sugar, but for salt an earthenware or glass vessel should be used. It is not advisable to put these foods or any others into cupboards in paper bags, because foods kept in this way make disorderly looking shelves and are easily accessible to vermin, which are always attracted to food whenever it is not well protected.
Canned goods bought in tin cans do not need very careful storage. It is sufficient to keep them in a place dry enough to prevent the cans from rusting. Foods canned in glass, however, should be kept where they are not exposed to the light, as they will become more or less discolored unless they are stored in dark places.
Flour, meals, and cereals stored in quantities develop mold unless they are kept very dry. For the storing of these foods, therefore, wooden bins or metal-lined boxes kept in a dry place are the most satisfactory.
STORING OF SEMIPERISHABLE FOODS
57. Practically all vegetables and fruits with skins may be regarded as semiperishable foods, and while they do not spoil so easily as some foods, they require a certain amount of care. Potatoes are easily kept from spoiling if they are placed in a cool, dry, dark place, such as a cellar, a bin like that shown in Fig. 16 furnishing a very good means for such storage. It is, of course, economical to buy potatoes in large quantities, but if they must be kept under conditions that will permit them to sprout, shrivel, rot, or freeze, it is better to buy only a small quantity at a time. Sweet potatoes may be bought in considerable quantity and kept for some time if they are wrapped separately in pieces of paper and packed so that they do not touch one another.
Carrots, turnips, beets, and parsnips can be kept through the winter in very much the same manner as potatoes. They deteriorate less, however, if they are covered with earth or sand. Sometimes, especially in country districts, such winter vegetables are buried in the ground out of doors, being placed at a depth that renders them safe from the attacks of frost. Cabbage will keep very well if placed in barrels or boxes, but for long keeping, the roots should not be removed. Pumpkin and squash thoroughly matured do not spoil readily if they are stored in a dry place.
Apples and pears may be stored in boxes or barrels, but very fine varieties of these fruits should be wrapped separately in paper. All fruit should be looked over occasionally, and those which show signs of spoiling should be removed
Source: Woman's Institute Library of Cookery
Other Chapters: The Problem of Food | Selection of Food | Food Substances | Food Value | Digestion and Absorption of Food | Preparation of Food | Methods of Cooking | Heat for Cooking | Utensils for Cooking | Preparing Foods for Cooking | Order of Work | Cooking Time Table | Care of Food | Menus and Recipes | Terms Used in Cookery