BACTERIA IN THE INDUSTRIES. 



103 



from the bag and place it in the ice-chest, cellar, or cooler until the milk is 

 wanted for use. 



Such certified milk would, in all probability, contain less than 1000 mi- 

 crobes per c.c, perhaps not more than 200 to 500 per c.c, whereas most of 

 the so-called certified milk found on the market contains from 1000 to 10,000 

 and more microbes per c.c. The bacterial content of fresh uncertified milk 

 ranges from 20,000 to several millions, although from 20,000 to 50,000 per 

 c.c. is the maximum number allowed by most boards of health. As already 

 stated, milk is an excellent culture medium for bacteria, and under favorable 

 temperature conditions the rate of development is very rapid. In the United 

 States the requirements of the bacteriological standardization of milk are 

 very variable and are rather arbitrarily fixed by the different boards of 

 health that may insist upon any standard at all. In some cities a summer 

 and a winter standard is recognized. 75,000 bacteria per c.c. may be the 

 winter standard, while 100,000 per c.c- is the summer standard. Nearly 

 all boards of' health admit that 3,000,000 bacteria per c.c. is the maximum 

 number which may be perniissible. 



Milk, on standing, should show no dirt deposit. This crude test is a 

 fairly reliable guide as to the sanitary conditions in the dair)dng establishment 

 and the rules of cleanliness that are observed. It has been shown that the 

 quantity of bacteria in freshly drawn milk is directly proportional to the 

 amount of dirt (sediment) present. A bottle or tumbler full of milk should 

 show no dirt sediment after standing for an hour or more. 



Good cows' milk should have from 3.5 to 3.75 per cent, of butter fat. It 

 is marketed in three forms: Full milk having all of the butter fat, half milk 

 or partially skimmed milk, and skimmed milk. Because of the variability 

 of milk which is partially skimmed, it would be wise to withdraw it from the 

 market. When milk is sold without further specification, full or unskimmed 

 milk is understood. It is unlawful to sell skimmed milk as milk, or without 

 designating it as skimmed milk. 



In some countries, as Germany for example, the rules and regulations di- 

 rected against dairies, dairying and the sale of milk, are very far-reaching, 

 and are strictly enforced by the local health authorities. Specific rules are 

 laid down as to what milk may or may not be marketed, how the cows are to 

 be kept, what cattle diseases render the milk unfit for use, how cows and milk- 

 ers must be prepared for the milking process, etc. The use of preservatives 

 is not permitted, because these substances reduce the digestibility of the 

 milk and because their use encourages lax and careless methods in the dairy- 

 ing establishments. 



The bovine disease most to be dreaded is tuberculosis. It is very prev- 

 alent among cattle, and the milk from tuberculous cows is a serious menace 

 to the health of those who use it, particularly to susceptible (by inheritance) 



