II 



BACTERIOLOGICAL METHODS IN FOOD AND 

 DRUGS LABORATORIES 



i. Introduction 



The study of the significance of bacteria in foods of all kinds is 

 one of the most important and interesting of scientific subjects 

 and one which has received much attention ever since the science 

 of bacteriology has become more highly developed as the result 

 of the perfection of the compound microscope. For a long 

 period of time the popular notion has prevailed that bacteria were 

 essentially harmful and to designate any substance as bacterially 

 contaminated was to pronounce it dangerous and to condemn it 

 without trial. We now know that many, in fact most bacteria, 

 are beneficent rather than harmful, and that many different 

 species of bacteria are concerned in the preparation of food 

 substances. It cannot be denied, however, that many kinds of 

 bacteria as well as other organisms are concerned in the pro- 

 duction of changes in food substances which we know to be highly 

 detrimental to the well being of the human race. It is the duty 

 of modern sanitary science to guard against disease and the 

 contamination of food substances through the invasion of patho- 

 genic and otherwise objectionable organisms. It is the work of 

 the food bacteriologist to detect objectionable contaminations in 

 foods and to aid in developing those processes and methods of 

 food .preparation and manufacture which will prevent the re- 

 currence of such contamination. The food bacteriologist will 

 center his attention on the following: 



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