PURE AND IMPURE FOODS. 



What a Man Eats He Is." 



Edited by C. F. La 

 Author of "On Citraconic, Itaconic and 



PREPARATION OF FOOD. 

 According to Professor W. O. Atwater, 

 who has for a long time conducted impor- 

 tant food investigation for the U. S. De- 

 partment of Agriculture, the cooking of 

 food has much to do with its nutritive 

 value. There are 3 chief purposes of 

 cooking. The first is to change the me- 

 chanical condition so that the digestive 

 juices can act on the food more freely. 

 The 2d is to make it more appetizing by 

 improving the appearance and flavor. Food, 

 which is attractive to the taste quickens the 

 flow of saliva and other digestive juices, 

 and aids digestion. The 3d is to kill by 

 heat any disease germs, parasites, or other 

 dangerous organisms the food may contain. 

 This is important and applies to both ani- 

 mal and vegetable foods. The cooking of 

 meats develops the pleasing taste and odor 

 of the extractives, also that due to the 

 browned fat and tissue ; softens and loosens 

 the protein (gelatinoids) of the connective 

 tissues ; and makes the meat more tender. 

 Extreme heat, however, tends to coagulate 

 and harden the albuminoids of the lean por- 

 tions, and weakens the flavor of extractives. 

 If the heating is carried too far, a burned 

 or charred product of bad flavor results. 

 Meats lose weight in cooking. A small 

 part of this is due to escape of meat juices 

 and fat, but the chief part of the material 

 lost is water. The nutritive value of meat 

 soup depends on the substances which are 

 dissolved out of the meat, bones, and gristle 

 by the water. In ordinary meat broth these 

 consist almost wholly of extractives and 

 salts, which are agreeable and often most 

 useful as stimulants, but have little or no 

 value as actual nutriment, since they neither 

 build tissue nor yield energy. The prin- 

 ciples which underlie the cooking of flsh 

 are essentially the same as with meats. 



In many vegetables valuable carbohy- 

 drates, chiefly microscopic starch grains, 

 are contained in tiny cells with thick walls 

 on which the digestive juices have little ef- 

 fect. Cooking, especially with the aid of 

 water, ruptures these walls and makes the 

 starch more soluble. The heat also cara- 

 melizes a portion of the carbohydrates and 

 produces agreeable flavors in this and other 

 ways. 

 In breads, cakes, pastry, and other foods 

 I prepared from flour, the aim is to make a 

 palatable and light porous substance, easily 

 broken up in the alimentary canal. Some- 

 times this is accomplished by means of 

 water and heat. The heat changes part of 

 the water in the dough to steam, which, in 



NGWORTHY, PH.D. 



Mesaconic Acids," " Fish as Food," etc. 



trying to escape, forces the particles of 

 dough apart. The protein (gluten) of the 

 flour stiffens about the tiny bubbles thus 

 formed and the mass remains porous even 

 after the steam has escaped. More often 

 other things are used to raise the dough, 

 such as yeast and baking powder. Baking 

 powder gives off carbon dioxid and the 

 yeast causes fermentation in the dough, by 

 which carbon dioxid is produced. This 

 acts as the steam . does, only much more 

 powerfully. When beaten eggs are used, 

 the albumen encloses air in bubbles which 

 expand, and the walls stiffen with heat, 

 thus rendering the food porous. 



Professor Atwater insists that scrupulous 

 neatness should always be observed in keep- 

 ing, handling, and serving food. If ever 

 cleanliness is desirable, it must be in the 

 things we eat, and every care should be 

 taken to insure it for the sake of health as 

 well as of decency. Cleanliness in this con- 

 nection means not only absence of visible 

 dirt, but freedom from undesirable bacteria 

 and other minute organisms, and from 

 worms and other parasites. If food, raw 

 or cooked, is kept in dirty places, peddled 

 from dirty carts, prepared in dirty rooms 

 and in dirty dishes or exposed to foul air, 

 disease germs and other offensive and dan- 

 gero.is substances can easily get in. 



Food and drink may be dangerous pur- 

 veyors of disease. The bacteria of fevers 

 sometimes find their way into drinking 

 water and milk, and bring sickness and 

 death to large numbers of people. Oysters 

 which are taken from the salt water where 

 they grow, and floated a short time in 

 brackish water near the mouth of a stream, 

 have been known to be infected by typhoid 

 fever germs, brought into the stream by 

 sewage from houses where the dejections 

 from" patients had been thrown into the 

 drains. Celery or t lettuce grown in soil 

 containing typhoid germs has been thought 

 to convey this disease. 



Food materials may contain parasites, 

 like tapeworms in beef, pork and mutton, 

 and trichinae in pork, which are injurious 

 and sometimes deadly in their effect. This 

 danger is not confined to animal foods. 

 Vegetables and fruits may become con- 

 taminated with eggs of numerous parasites 

 from the fertilizers applied to them. Raw 

 fruit and vegetables should always be thor- 

 oughly washed before serving, if there is 

 any doubt as to their cleanliness. If the 

 food is sufficiently heated in cooking, all 

 organisms are killed. 

 Sometimes food undergoes decomposition 



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