54 Dairy Bacteriology. 



content. To accomplish these results requires such strin- 

 gent control as to increase greatly the cost of the pro- 

 duct. Pure, clean milk can be produced at a very slight 

 increase in cost over the regular expense of milk pro- 

 duction, if the right kind of attention is given to certain 

 details of a practical character. Improvement in our 

 milk supplies must largely come from this source, for 

 any improvement to be permanent must be made to pay, 

 and it requires considerable education to secure the co- 

 operation of consumers and their willingness to 'pay for 

 any material increase in the quality of the product. 



In the foregoing factors concerned in the contamina- 

 tion of milk, it is of course impossible to measure accur- 

 ately the influence of the different sources of infection, 

 as these are continually subject to variation in every 

 case. As a rule, the most important factors are those 

 pertaining to the utensils and the condition of the ani- 

 mal herself. If these two factors are brought 'under rea- 

 sonable control, the major portion of contamination that 

 ordinarily obtains is done away with. The application 

 of the remedial or preventive measures heretofore men- 

 tioned will greatly reduce the germ content of the milk. 



Cooling of milk on farm. Bacterial growth is directly 

 related to temperature conditions, and with summer 

 temperatures, such development goes on apace, unless it 

 is checked by early cooling. The larger portion of bac- 

 teria that find their way into milk, especially thosa that 

 are previously in contact with the air, are in a dormant 

 condition, and are therefore not stimulated into immedi- 

 ate growth, unless reasonably high temperatures prevail. 

 In milk, which comes from the animal at blood heat, this 

 growth is greatly stimulated. To counteract this effect, 

 milk should be chilled as soon after milking as possible. 



