Dairying 383 



cheese. The rich flavor of these products is due largely to 

 these bacteria. If milk sours at a high temperature, an unde- 

 sirable type is likely to grow. These produce gas as well as 

 lactic acid and are responsible for so-called gassy curd when 

 the milk is made into cheese. Those of another type destroy 

 the casein and albumin of the milk and cause putrefaction and 

 bad odors. This type is, of course, undesirable. 



Disease germs are often carried in the milk, especially 

 those causing typhoid fever, tuberculosis, diphtheria, and 

 scarlet fever. Milk may be- 

 come contaminated by bac- 

 teria from the udder itself, 

 but this contamination is 

 usually harmless unless the 

 udder is affected with tuber - 

 culosis, garget, or some form ^ 

 of inflammation. The great- 

 est number of bacteria in 

 milk come from the dust of FlG . 164 . _ T his diagram shows the 

 the air, the dirt and manure rapidity with which bacteria multiply 



, i , , i n i c i n milk not properly cooled. A single 



On the Udder and flanks Ot bacterium (a) in 24 hours multiplied 



the cow, from the clothes of to 5 ( & ) in milk ke pt at 50 F - ; ( c > repre- 



,, -n -. c , sents the number that developed from a 



the milker, and trom unclean single bacterium kept 24 hours at 70 F. 

 utensils. Cleanliness about 



a stable and dairy-house is, therefore, a very important means 

 of reducing the number of bacteria in milk. 



195. Production of sanitary milk. Healthy cows are most 

 essential to the production of sanitary milk. Milk from dis- 

 eased cows is likely to contain disease-producing bacteria. 

 At least once a year the cows should be tested for tuberculosis 

 by a competent veterinarian and all animals that show reac- 

 tion should be removed from the herd. All cows added to 

 the herd should be tuberculin-tested. If at any time the cows 

 give slimy, ropy, watery, or otherwise abnormal milk, it should 

 not be used. 



