Human Foods and Their Nutritive Value - Harry Snyder (e book reader pc TXT) 📗
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278. Economic Value of a Pure Water Supply.—From a financial point of view, the money spent in securing pure water is one of the best investments a community can make. Statisticians estimate the death of an adult results in a loss to the state of from $1000 to $5000; and to the losses sustained by death must be added those incurred by sickness and by lessened quality and quantity of work through impaired vitality,—all caused by using poor drinking water. Wherever plants have been installed for improving the sanitary condition of the water supply, the death rate has been lowered and the returns to the community have been far greater than the cost of the plant. Impure water is the most expensive food that can be consumed.
CHAPTER XX FOOD AS AFFECTED BY HOUSEHOLD SANITATION AND STORAGE279. Injurious Compounds in Foods.—An ordinary chemical analysis of a food determines only the nutrients, as protein, carbohydrates, and fats; and unless there is reason to believe the food contains injurious substances no special tests for these are made. There are a number of poisonous compounds that foods may contain, and many of them can but imperfectly be determined by chemical analysis. Numerous organic compounds are produced in foods as the result of the workings of microörganisms; some of these are poisonous, while others impart only special characteristics, as taste and odor. The poisonous bacteria finding their way into food produce organic compounds of a toxic character; and hence it is that the sanitary condition of a food, as influenced by preparation and storage, is often of more vital importance than the nutrient content.[95]
Fig. 65.—Tuberculosis Bacilli. (After Conn.) Often present in dust particles and contaminated foods.
280. Sources of Contamination of Food.—As a rule, too little attention is given to the sanitary handling and preparation of foods. They are often exposed to impure air and to the dust and filth from unclean streets and surroundings, and as a result they become inoculated with bacteria, which are often the disease-producing kind. Gelatine plates exposed by bacteriologists under the same conditions as foods develop large numbers of injurious microörganisms. In order to avoid contamination in the handling of food, there must be: (1) protection from impure air and dust; (2) storage in clean, sanitary, and ventilated storerooms and warehouses; (3) storage of perishable foods at a low temperature so as to retard fermentation changes; and (4) workmen free from contagious diseases in all occupations pertaining to the preparation of foods. Ordinarily, foods should not be stored in the paper wrappers in which they are purchased, as unclean paper is often a source of contamination.
281. Sanitary Inspection of Food.—During recent years some state and city boards of health have introduced sanitary inspection of foods, with a view of preventing contamination during manufacture and transportation, and this has done much to improve the quality and wholesomeness. Putrid meats, fish, and vegetables are not allowed to be sold, and foods are required to be handled and stored in a sanitary way. Next to a pure water supply, there is no factor that so greatly influences for good the health of a community as the sanitary condition of the food. While the cooking of foods destroys many organisms, it often fails to render innocuous the poisons which they produce, and furthermore the unsound foods when cooked are not entirely wholesome, and they have poor keeping qualities.
Often meats, vegetables, and other foods eaten uncooked, as well as the numerous cooked foods, are exposed in dirty market places, and accumulate large amounts of filth, and are inoculated with disease germs by flies. Protection of food from flies is a matter of vital importance, as they are carriers of many diseases. In the case of typhoid fever, next to impure drinking water flies are credited with being the greatest distributors of the disease germs.[96]
Fig. 66.—Diphtheria Bacilli. (After Conn.) Often present in dust particles and in food unprotected from dust.
282. Infection from Impure Air.—The dust particles of the air contain decayed animal and vegetable matter in which bacteria are present; these find their way into the food when it is not carefully protected, into the water supply, and also into the lungs and other organs of the body. When foods are protected from the mechanical impurities which gain access through the air, and fermentation is delayed by storage at a low temperature, digestion disorders are greatly lessened. From a sanitary point of view, the air of food storerooms and of living rooms should be of equally high purity. When foods are kept in unventilated living rooms, they become contaminated with the impurities thrown off from the lungs in respiration, which include not only carbon dioxid, but the more objectionable toxic organic materials.
Vegetable foods need to be stored in well-ventilated places, as the plant cells are still alive and carrying on life functions, as the giving off of carbon dioxid, which is akin to animal respiration; in fact, it is plant-cell respiration. Provision should be made for the removal of the carbon dioxid and other products, as they contaminate the air. When vegetable tissue ceases to produce carbon dioxid, death and decay set in, accompanied by fermentation changes.
283. Storage of Food in Cellars.—Cellars are often in a very unsanitary condition, damp, poorly lighted, unventilated, and the air filled with floating particles from decaying vegetables. The walls and shelves absorb the dust and germs from the foul air and are bacterially contaminated, and whenever a sound food is stored in such a cellar, it readily becomes inoculated with bacteria. There is a much closer relationship existing between the atmosphere of the cellar and that of the house than is generally realized. An unclean cellar means contaminated air throughout the house. When careful attention is given to the sanitary condition of the cellar, many of the more common diseases are greatly reduced. Cases of rheumatism have often been traced to a damp cellar. In some localities where the cellars are unusually unsanitary, there is in the season of spring rains, when they are especially damp and contain the maximum of decayed vegetation, a prevalence of what might be called "cellaritis." The symptoms differ and the trouble is variously attributed, but the real cause is the same, although overlooked, for, unfortunately, doctors do not visit the cellar.
Fig. 67.—Dung Fungus.
(After Butters.) Often present on surface
of unclean vegetables.
Cellars should be frequently cleaned and disinfected, using for the purpose some of the well-known disinfectants, as formaline, bleaching powder, or a dilute solution of carbolic acid. It has been found in large cities, when the spread of such diseases as yellow fever was imminent, that a general and thorough cleaning up of streets and cellars with the improved sanitary conditions resulting greatly lowered the usual death rate.
284. Sunlight, Pure Water, and Pure Air as Disinfectants.—The most effectual and valuable disinfectants are sunlight, pure water, and pure air. Many kinds of microörganisms, particularly those that are disease-producing, are destroyed when exposed for a time to sunlight. The chemical action of the sun's rays is destructive to the organic material which makes up the composition of many of these organisms, while higher forms of organic life are stirred into activity by it. The disinfecting power of sunlight should be made use of to the fullest extent, not only in the house, but plenty of sunlight should also be planned for in constructing barns and other buildings where milk-and meat-producing animals are kept. Pure water is also a disinfectant, but when water becomes polluted it loses this power. Many disease-producing organisms are rendered inactive when placed in pure water. Water contains more dissolved oxygen than air, and apparently a portion of the oxygen in water is in a more active condition than that in air. Pure air, too, is a disinfectant; the ozone and hydrogen peroxide and oxides of nitrogen, which are present in traces, exert a beneficial influence in oxidizing organic matter. Fresh air and sunlight, acting jointly, are nature's most effectual disinfectants. Sunshine, fresh air, and pure water are a health-producing trinity. In discussing the importance of pure air, water, and sunlight, Ellen H. Richards[97] says:
"The country dweller surrounds his house with evergreens or shade trees, the city dweller is surrounded with high brick walls. Blinds, shades, or thick draperies shut out still more, and prevent the beneficial sunlight from acting its role of germ prevention and germ destruction. Bright-colored carpets and pale-faced children are the opposite results which follow. Sunlight, pure air, and pure water are our common birthright which we often bargain away for so-called comforts."
And Dr. Woods Hutchinson says of sunlight:
"It is a splendid and matchless servant in the promoting of healthfulness of the house, for which no substitute has yet been discovered. It is the foe alike of bacilli and the blues; the best tonic ever yet invented for the liver and for the scalp, and for everything between, the only real complexion restorer, and the deadliest foe of dirt and disease."
Fig. 68.—Dirt and Manure
Embedded In Surface of Celery.
285. Utensils for Storage of Food.—In order that dishes and household utensils may be kept in the best sanitary condition, they should be free from seams, cracks, and crevices where dust and dirt particles can find lodgment. From the seams of a milk pail that has not been well washed, decaying milk solids can be removed with the aid of a pin or a toothpick. This material acts as a "starter" or culture when pure, fresh milk is placed in the pail, contaminating it and causing it to become sour. Not only is this true of milk, but also of other foods. Wooden utensils are not satisfactory for the handling, storage, or preparation of foods, as it is difficult to keep wood in a sanitary condition. Uncleanliness of dishes in which foods are placed is too often caused by the use of foul dishcloths and failure to thoroughly wash and rinse the dishes. It is always well to rinse dishes with scalding water, as colds and skin diseases may be communicated from the edges of drinking glasses, and from forks and spoons, and, unless the dish towels are kept scrupulously clean, it is more sanitary to drain the dishes than to wipe them.
286. Contamination from Unclean Dishcloths.—When the dishcloth is foul, the fat absorbed by the fibers becomes rancid, the proteids undergo putrefaction changes with formation of ill-smelling gases containing nitrogen, the carbohydrates ferment and are particularly attractive to flies, and all the various disease germs collected on the surface of the dishcloth are, along with the rancid fat and other putrifying materials, distributed over the surface of the dishes with which the cloth comes in contact.
Fig. 69.—Contamination of Well Water From Surface Drainage. (After Farmers' Bulletin, U. S. Dept. Agr.)
287. Refrigeration.—At a low temperature the insoluble or unorganized ferments become inactive, but the chemical ferments or enzymes are still capable of carrying on fermentation. Thus it is that a food, when placed in a refrigerator or in cold storage, continues to undergo chemical change. An example of such enzymic action is the curing of beef and cheese in cold storage. A small amount of ventilation is required when foods are refrigerated, just sufficient to keep up a slight circulation
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