386 



MICROBIOLOGY OF MILK AND MILK PRODUCTS 



pathogenic organisms, possibly with the exception of Bad. tubercu- 

 losis, get into milk, either directly or indirectly, from human patients 

 suffering with the particular disease. 



Factors Influencing the Development of Microorganisms in 



Milk 



— ^The number of microorganisms fovmd in fresh milk shows its bac- 

 terial condition at that time, but it gives little idea of the organisms 

 which may be found in the same milk at later periods. There are 

 many factors to be considered if we wish to study the development 

 of the various types which get into ordinary milk. These factors 

 may be considered briefly under the following heads: 



Initial Contamination. — Fresh milk varies widely in the number 

 of organisms which it contains as a result of the conditions under 

 which it has been produced. There are differences not only in the 

 numbers of organisms but also in the species which may be found in 

 different samples of fresh milk. Both of these factors are important 

 in the later changes which may take place. The effect of numer- 

 ical initial contamination may be seen in the following tables where 



Effect of Initial Contamination on Development of Bacteria and Keeping 



QiTALiTV OF Milk 



Milk Having Moderately High Initial Contamination 



