1326 The Cornell Reading-Courses 



by growth of micro-organisms in the milk. The first change may be 

 brought about by foreign taints absorbed in the milk before it leaves 

 the cow, in case she has eaten, especially if only a short time before milk- 

 ing, any strong feed such as__onions, turnips, or cabbage. This can be 

 avoided either by preventing the cow from eating these strong feeds or 

 by giving them soon after milking; in the latter case, the strong gases in 

 the feeds have time to work out of the cow's body before the next milking 

 time. Most of the undesirable taints in milk, however, are caused after 

 the milk has been drawn from the cow and are the result of exposure to 

 the odor of some strong material. Frequently, milk is badly tainted 

 during the milking process by silage in the stable, the atmosphere being 

 filled with the odor. It is surprising how quickly milk will absorb such 

 odors; it is often injured very seriously during its ten or fifteen minutes 

 exposure to a stable atmosphere where there is either an odor of silage 

 or a strong stable odor resulting from lack of ventilation. Milk is very 

 frequently spoiled after it reaches the kitchen, by being placed in an ice 

 chest with other strong-smelling foods. It is a curious fact that any 

 absorbed odor in milk gives it a very disagreeable taste, even 

 when the odor in itself is pleasant. This is shown when odors are 

 absorbed from fresh strawberries or pineapple. Ofttimes, merely 

 the odor from a close, poorly ventilated ice chest or pantry will spoil 

 milk for use. If possible, milk should always be kept in closed 

 receptacles and never exposed in an open dish or pan in an ice chest 

 with other foods. 



The changes under the second class mentioned above may vary greatly 

 in nature, but all are caused by the growth of different kinds of micro- 

 organisms that get into the milk after it has been drawn from the cow. 

 These little organisms are everywhere present, especially where there is 

 any dust or dirt: the surface of the cow's body is always covered with 

 them, and frequently, also, they are numerous in the stable atmosphere; 

 the dairy utensils, if not properly cleaned and scalded, may contain 

 large numbers; the hands and clothing of the persons handling the 

 milk may also have on them considerable numbers of these minute 

 organisms. The length of time that milk will keep without spoiling, 

 and the kind of undesirable changes that takes place in it, are 

 directly dependent on the number and kinds of organisms therein. 

 It will be seen, therefore, that it is desirable to keep the number 

 of bacteria as small as possible. Under ordinary conditions the 

 greater part of the organisms that get into milk come from the 

 sources mentioned above during the milking and subsequent handling. 

 The number that may get in depends on the conditions of cleanli- 

 ness in the stable and the care used in handling the milk. The effect 



