186 FARM ANIMALS 



brushed from the cows before milking, falls into 

 the milk in large quantities at milking time and 

 thus contaminates the milk not only in the way 

 of the filth introduced, but by the numerous 

 bacteria carried on this dirt. It is practically 

 impossible under ordinary dairy conditions to 

 prevent some dirt from falling into the milk. 

 by careful grooming and washing of the teats 

 and milking with dry hands, however, the amount 

 of dirt may be reduced to a minimum. Experi- 

 ments have shown, with cows kept in an ordinary 

 condition, but not groomed, that during the 

 process of milking one ounce of dirt is added to 

 each two hundred and seventy-five pounds of 

 milk. 



The presence of dirt in milk is always an evidence 

 of unsanitary conditions or methods on the part 

 of the dairyman. The mere presence of filth, 

 however, may not be injurious in any way in 

 itself. Filth in milk is always associated with 

 an increase in the number of bacteria in the 

 milk and this is a much more serious proposition, 

 for a greater number of bacteria in milk sour 

 the milk quickly and are likely to produce colic 

 and other digestive disturbances in children and 

 to a less extent in adults. 



Milk as it is secreted in the actual glandular 

 tissue contains no bacteria. Many bacteria, how- 

 ever, succeed in penetrating into the milk duct 

 of the teats and, therefore, the milk in the milk 

 cisterns contains some bacteria. Milk is one 

 of the best of nutritive media for the growth of 

 bacteria and, therefore, their numbers multiply 

 with astounding rapidity. Moreover the number 

 of bacteria in milk is suddenly added to from 

 other sources such as the air, cow's skin, the 



