CHAPTER VII 



TREATMENT OF MILK FOR MARKET 



IT is impossible to make any statement as to the number of 

 bacteria liable to be found in milk. There may be as few as 

 3,000 or as many as 200,000,000 per c.c. Even in fresh milk 

 the number varies widely, as we have seen, and curiously 

 enough wide variations may occur on the same farm, under 

 apparently similar conditions. Sometimes a dairy that is pro- 

 ducing milk regularly with few bacteria will, in one or two days, 

 find the number enormously increased, without being able to 

 find any explanation for the fact. The number found at any 

 later hour in any sample is still more variable and will depend 

 upon three factors: i. The cleanliness of the conditions under 

 which the milk was produced. 2. The age of the milk. 3. The 

 temperature at which it has been kept. Of these three factors 

 the latter is most important in determining the numbers. 



There has grown up in recent years a strong demand that the 

 number of bacteria in milk offered in market shall be kept low. 

 While the presence of large numbers is liable to a very errone- 

 ous interpretation, no doubt it is desirable to keep the bacteria 

 down to as small a number as possible. The question how this 

 can be done is forcing itself more and more on the attention of 

 the milk producer. We have noticed in the last chapter the 

 various devices which are being adopted in dairies for reducing 

 the original bacterial contamination. We have next to notice 

 methods adopted for placing milk containing as few bacteria 

 as possible in the hands of the consumer. 

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