The Bulletin. 5 



flavor, texture and general quality of the home-made product can 

 be made suj^erior to the product of the average factory. 



STERILIZATION. 



Minute forms of life, Avhich Ave call bacteria, are present every- 

 where in untold numbers. The air we breathe, the water we^ drink, 

 and the food Ave eat are teeming Avith them. These bacteria are 

 practically the sole cause of the ''spoiling" or fermenting of the 

 various fruits and vegetables. The reproduction of bacteria, which 

 is A^ery rapid, is brought about by one of tAvo processes. The bac- 

 terium either divides itself into tAA'o parts, making two bacteria 

 AA-here one existed before, or else reproduces itself by means of spores. 

 Spores may be compared Avith the seed of an ordinary plant. These 

 spores present the chief difficulty in canning the products of the 

 orchard and garden. 



All forms of bacteria are killed by complete sterilization. This 

 is nothing more than enclosing the products to be sterilized in jars 

 or cans that can be sealed air-tight and submitting them to heat of 

 sufficient temperature for a time, long enough to destroy the bacteria 

 that cause the raw material to spoil. Sterilization is readily ac- 

 complished by the use of boiling water. There are three different 

 ways by Avhich this can be~ done. While the parent bacteria can be 

 killed at the temperature of boiling Avater, their spores retain their 

 vitality for a long time even at that temperature. In large com- 

 mercial factories, sterilization is accomplished by subjecting the 

 cans containing the various products to steam under pressure. By 

 this process the temperature is raised to a degree higher than that 

 of boiling Avater, thereby killing both bacteria and spores at the same 

 time. Smaller factories and the different home-canning outfits 

 usually make use of the ''open-kettle" process. Here the cans are 

 submerged in boiling Avater and kept at that temperature for a time 

 sufficient to destroy bacteria and spores. The third process, known 

 as fractional sterilization, is that of keeping cans or jars in boiling 

 water for a specified time upon each of tAvo or three consecutive 

 days. 



The process of boiling upon consecutive days is the safest method 

 and is much to be preferred in home canning. The first day's boiling 

 kills practically all the bacteria, but does not kill the spores. As 

 soon as the jars or cans cool, these spores develop and a new lot of 

 bacteria begin their destructiA'e work on the contents. The second 

 day's boiling kills this ncAV lot of bacteria before they have had 

 time to produce spores. Boiling the third day is not ahvays neces- 

 sary, but it is advisable in order to be sure that the sterilization 

 is complete. 



