230 NEBRASKA STATE HORTICULTURAL SOCIETY 



the top and will prevent any outside air from entering. The jars can 

 now be removed and cooled or allowed to stand in the boiler until the 

 next day. 



On the second day raise the spring at the side of the jar. This will 

 relieve any pressure from steam that might accumulate inside the jar 

 during the second cooking. Place the jars again in the boiler and 

 boil for one hour. Clamp on the top as on the preceding day and allow 

 them to cool. Repeat this operation on the third day. In removing 

 the jars from the boiler be careful not to expose them to a draft of 

 cold air while they are hot, as a sudden change in temperature is likely 

 to crack them. 



After the sterilization is complete the jars may be set aside for a 

 day or two and then tested. This is done by releasing the spring at the 

 side and picking up the jar by the top. If there has been the least bit 

 of decomposition, or if sterilization has not been complete the top will 

 come off. This is because the pressure on the top has been relieved 

 by the gas formed by the bacteria. In this case it is always best 

 to empty out the corn and fill up the jar with a fresh supply. If can- 

 ning fruits or some expensive vegetable, however, examine the contents 

 of the jar and, if the decomposition has not gone far enough to injure 

 the flavor, place it once more in the boiler and sterilize over again. If 

 the top does not come off, you may feel sure that the vegetable is keeping. 



Bacteria are very resistant to heat. They thrive in products like milk 

 and in meats and vegetables rich in protein, such as peas, beans, etc. All 

 known species of molds require air in which to work. This is not true 

 of bacteria, certain species of which will live and cause vegetables to de- 

 compose even when no air is present. When these particular species are 

 present the exclusion of air is no safegraud against decay, unless the 

 vegetable is first thoroughly sterilized. Bacteria are so small that they 

 can only be seen with a microscope, and they reproduce themselves with 

 amazing rapidity. One bacterium under favorable conditions will pro- 

 duce about twenty millions in the course of twenty-four hours. Accord- 

 ingly, certain vegetables spoil more rapidly than others because they 

 furnish a better medium for bacterial growth. 



The reproduction of bacteria is brought about by one or two pro- 

 cesses. The germ either divides itself into two parts, making two bac- 

 teria where one existed before, or else produces itself by means of 

 spores. These spores may be compared with seeds of an ordinary plant, 

 and they present the chief difficulty in canning vegetables. While the 

 parent bacteria may be readily killed at the temperature of boiling water^ 

 the seeds retain their vitality for a long time even at that temperature, and 

 upon cooling will germinate, and the newly formed bacteria will begin 

 their destructive work. Therefore it is necssary, in order to completely 

 sterilize a vegetable, to heat it to boiling point of water and keep it at 

 that temperature for about an hour, upon two or three successive days or 

 else keep it at the temperature of boiling water for a long period of time 

 — ^about five hours. The process of boiling upon successive days is the 



