NUMBER AND SOURCE OF BACTERIA IN MILK 253 



area was found to be from about 450 to 2400 per 

 minute. The use of 

 milk-pails with nar- 

 rower mouths than 

 those in common 

 use has been found 

 to reduce contami- 

 nation and improve 

 the keeping quality 

 of the milk (Figs. 

 41-44). 



Flies also carry 

 many objectionable 

 bacteria from putre- 

 fying material Upon jr IG . 43 ._ Plate exposed one minute in cowshed after 



x 



which they settle, 



and are responsible for 



FIG. 44. Plate exposed one minute after cowshed was 

 brushed out. 



giving the cows hay. 



the introduction of these 

 into milk in which 

 they drown. 



Milking cans, 

 pails, milk coolers, 

 and other vessels 

 on the farm, un- 

 less very carefully 

 cleaned, are also 

 fruitful sources of 

 contamination. 

 The cansorchurns 

 in which the milk 

 is despatched by 

 rail are respon- 

 sible for a very 

 large share of the 



