404 BENEFICIAL ACTIVITIES OF BACTERIA 



If cabbage is finely chopped, salted, and packed tightly in 

 jars or barrels, it will undergo a chemical change. The salt will 



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When bacteria absorb and use food, they give off acid wastes. The wastes of disease- 

 producing bacteria are called toxins. 



extract from the cabbage the juice which is a good medium for 

 the growth of lactic-acid bacteria. This will attack the tissues of 

 the cabbage, changing it to sauerkraut. Meat is made tender 

 by the action of bacteria. When meat is fresh, that is, soon 

 after the animal is killed, it is tough and more or less tasteless. 

 Bacteria attack the muscles and connective tissue, loosen the 

 fibers, and give the meat a taste. Meat is usually kept for some 

 time to permit this bacterial attack. This is the beginning of the 

 decay process. The process must not go too far or products that 

 are objectionable are formed, and the meat is said to be tainted. 



Ensilage is prepared for stock by packing finely chopped fodder 

 in a silo. Bacteria and enzymes will attack the tissues of the 

 fodder, causing it to change in appearance, flavor, and nutritive 

 value. 



Bacteria in other industries. Sponges are animals. The fairly 

 hard commercial sponge is really the skeleton of the animal. This 

 skeleton is composed of substances secreted by the cells of the 

 animal. The sponges of commerce are prepared by cutting their 

 attachment to the sea floor. The sponges are spread out on the 

 seashore and bacteria destroy the soft organic parts, lea\dng the 

 fibrous, horny framework or skeleton. This process is knowm as 

 curing. The exoskeletons are then thoroughly washed and 

 cleaned and sold for commercial uses. 



