374 MILK BACTERIOLOGY 



by. the following experiment reported by Stocking. The average of 

 19 tests with two milkers, one who had had no training in dairy sanita- 

 tion, and one who had, showed 17,105 bacteria per c.c. for the 

 untrained man and 2455 for the trained man. The only difference 

 was the knowledge possessed by the trained man. 



Even more important than the surroundings in contaminating 

 milk are the utensils. Many buckets are wrongly constructed or 

 not scalded each time so that every seam contains hidden away 

 millions of bacteria. These immediately grow on reaching the 

 fresh, warm milk. Then the strainer may contain a good seeding 

 of bacteria. It would be a great step in advance could the strainer 

 by some means be done away with, for then greater care would be 

 taken in the production of milk; otherwise, it would be unsalable. 

 The condition is somewhat similar to that which existed when it wus 

 first suggested that bread be wrapped. There was a baker's con- 

 vention and the subject had come up for consideration and the 

 members had practically agreed that all bread offered by them should 

 be wrapped, when an old veteran arose and said, "If we wrap our 

 bread in white paper and handle it as we do now the paper will be 

 so dirty that when it reaches the consumer he will refuse to buy." 

 So it is with milk; if it had to be sold in the condition in which it 

 comes at times from the barn, it would be refused. Not that the 

 strainer reduces the number of bacteria in the milk, for it does not. 

 It only removes the particles which are visible to the naked eye after 

 they have been washed nearly free from bacteria. 



Prucha and coworkers studied the influence of all the utensils 

 that normally come into contact with the milk both at the barn 

 and at the dairy. They found that when they were all carefully 

 steamed the germ content of the milk in the bottles was about 4566 

 bacteria per c.c. When similar conditions obtained, except that the 

 steaming of the utensils was omitted, the germ content of the milk 

 approximated 257,240 bacteria per c.c. 



Of all the various utensils coming into contact with the milk at 

 the barn and at the dairy, it was found that the clarifier and the 

 bottle-filler, when unsteamed, proved to be the most prolific sources 

 of contamination. 



It would, therefore, seem that the most important factor in 

 producing good milk is the scrupulous cleanliness of the milk uten- 

 sils and not so much surroundings, as has been so much taught in the 

 past. 



It is difficult to accurately measure the contamination in transit 

 and on the sellers' premises, but it is quite evident that at times it is 

 large. Orr reported average increases as high as 22.7 per cent., 

 whereas it should be zero under ideal conditions. 



Growth of Bacteria in Milk. Saprophy tic and many pathogenic 

 bacteria multiply in milk so that the number found in milk is 



