EFFECT OF TEMPERATURE 37 



though tightly closed in an atmosphere saturated with 

 moisture and abundantly sown with mold spores. In cold- 

 storage houses, where the temperature is below freezing, 

 there is no molding. If the temperature is just above 

 freezing, molding is almost prevented. The ice chest also, 

 though much warmer, very decidedly checks the tendency 

 in most foods to mold. Cheese, for example, after being 

 cut, should be kept in a closed dish, to prevent its drying 

 too rapidly ; but it molds rapidly when thus covered. If 

 the dish be placed in an ordinary refrigerator, it will keep 

 a long time. 



Killing by Heat. In considering the relation of tem- 

 perature to molds a fact of great importance is that high 

 heat will always destroy molds and their spores. A tem- 

 perature considerably below boiling, 150 or 160, is quite 

 sufficient to destroy the mycelium of the molds, although 

 the spores may resist this temperature ; but a temperature 

 of boiling is necessary to kill the spores. Hence any 

 food which has begun to mold, and which is of a character 

 to allow heating, may be protected from the further growth 

 of the mold by boiling. A temperature somewhat below 

 boiling will check mold growth, though not actually kill- 

 ing the spores. This method of treatment will be possible 

 for many preserves, canned foods, or any food that has 

 been previously cooked. It may be applied to preserves, 

 sauces, jellies, mince-meat, and even pickles. It would 

 not be practicable, however, with foods whose flavor is 

 destroyed by cooking. Fresh fruit which has begun to 

 mold cannot be treated in this way without destroying 

 the original fruit flavor and giving in its place the taste 

 of fruit preserves or sauce. It is always necessary to 



