The Farm Table. 683 



and they will die if deprived of moisture and food. But the spores, like 

 the seeds of plants, will live for a long time without moisture or food. 

 Extreme cold may not kill them. Extreme heat will destroy the life in 

 _ the spore, the same as it does in the seed of the plant. There are some 

 plants and seeds that will stand great heat and cold without injury. 

 Among the bacteria there are some kinds that are killed by a temperature 

 as low as 160°, while there are others that must be kept at a temperature 

 of 212° for an hour or more, to make sure of destroying all life. When 

 we sterilize a substance we destroy all life or sources of life in and about 

 it. We have seen that living and growing plants are killed by extreme 

 cold, but more surely and easily are they killed by extreme heat. This 

 is also true of yeasts and molds and of many kinds of bacteria. We 

 know that seeds of plants, when dry, are not injured by extreme cold, 

 but the germs may be killed by boiling, steaming, or baking for some time. 

 The spores of yeasts, molds, and bacteria, like the seeds of plants, are not 

 injured by cold, but they may be killed by boiling, steaming or baking. 



Bacteria, yeast and mold plants and spores are liable to be on and 

 in all food, and on all utensils. We now know that these little organisms 

 spoil food by growing in or on them, and that if we wish to keep foods 

 for any length of time we must protect the foods from them. We could 

 dry the foods and as long as they were kept perfectly dry the little plants 

 could not injure them, because, for want of moisture, they could not 

 grow on or in the food. But canned food is more like the fresh article, 

 and so nearly everyone prefers this method of preserving foods, particu- 

 larly fruits and vegetables. So we kill the live plants, and the spores 

 that are on and in the fruit, and on the surface of the jars and utensils. 

 In large establishments, where there is an abundance of steam, all the 

 utensils are thoroughly steamed. The food is treated with heat in various 

 ways. In the farm house the utensils can be sterilized by boiling them. 

 The food may be sterilized by boiling, baking or steaming. To sterilize 

 jars and utensils, have large stew-pans washed clean. Fill them with 

 fruit jars and their covers. Put on the stove and put in enough cold 

 water to cover them. Heat gradually to the boiling 

 point, and boil ten or fifteen minutes. The jars must 

 be taken one by one from the boiling water at the 

 moment they are to be filled. The covers of the jars 

 are to be taken from the boiling water just as they are 

 to be put on the jars. Jelly tumblers are to be steril- 

 ized the same as the fruit jars. All the utensils em- Fig. 185. — A grad- 

 ployed in the work may be sterilized by putting them 

 into boiling water and boiling ten or fifteen minutes. 



Knowing, as we do that the plants and spores of bacteria, yeasts and 



