EXPERIMENT STATION BULLETINS. 



175 



have the key to the management of either good or had milk. Good milk will 

 remain good indefinitely if kept sufficiently cold and bad milk will not grow 

 worse if kept under the same conditions. Conn has done the most recent and 

 most exhaustive work along this line. His table in Bulletin No. 26, of the 

 Connecticut Experiment Station, illustrates this very graphically. 



Number of bacteria per c. cm. in milk kept at different temperatures. 



>irumber at outset. 



■46,000 

 47,000 

 50,000 



In 12 hrs. 

 at 50°. 



30,000 

 44,800 

 35,000 



In 12 hrs. 

 at 50°. 



249,500 

 360,000 

 800,000 



In 50 hrs. 

 at 50° 



1 . 500, 000 

 127,500 

 160,000 



In 50 hours, or at 



time of 



curdling at 70° 



542,000,000 

 792,000,000, 36hra. 

 2,560,000,000, 42 hra. 



No. hrs. to 



curdling 



at 50° 



190 

 289 

 172 



No. hrs. to 

 curdling 

 at 70°. 



56 

 36 

 42 



It is easily seen from the above how important it is that the milk be cooled, 

 that it be cooled as soon after milking as feasible, and that it be kept cool until 

 consumed or used for the manufacture of milk products. 



Cold checks the development of micro-organisms. The freezing temperature 

 is, of course, better than 40° F.; 40° F. is better than 50° F.; 50° F. is better 

 than 60° F.; 60° F. is better than 70° F.; and 70° F. is better than 90° F. for re- 

 tarding the growth of micro-organisms. It follows from this .that milk should be 

 cooled at as low a temperature as possible immediately after milking and be 

 Icept cool. 



To accomplish the cooling of milk, any cold, extensive surface over which 

 the milk may run will be satisfactory if in a clean room. Ice should be used if 

 possible; if this is not available, employ running cold water. If coolers, such as 

 the Starr or Champion, are not procurable, a tank of cold running water into 

 ■which sets the can of milk, may be very advantageously substituted, but it is 

 -not so valuable. Under such conditions the milk should be stirred continuously 

 until cool, otherwise an hour or two will be necessary for lowering the tempera- 

 ture of the milk to that of the water. Time should not be wasted in this 

 manner, for the micro-organisms are usually very active at this stage. 



IX. MILKIXG IN THE STABLE. 



Little need be said concerning this subject because what has already been 

 hinted at in the discussion of the dust and dirt of the stable will be applicable; 

 and, further, the absorption of gases has been mentioned under aeration and 

 will furnish pertinent material. These are matters which serve as our reason 

 "for condemning the common practice of allowing open pails and open cans of 

 milk which are still warm to stand in the stable. Such practices are especially 

 bad after feeding or bedding because at such times the amount of dust and 

 dirt is materially increased. If 3,600,000 germs can fall into a milk pail during 

 five minutes, we may ask how many will fall into a ten gallon can exposed in 

 the stable while it is being filled by one milker? 



Again, we have learned that milk absorbs gases. We know that constantly 

 there are going off from fresh milk gases which are noticeable to our olfactory 

 nerves. It must not be supposed that these gases pass off without others of the 

 stable taking their place. It is an interchange of gases rather than a simple 

 elimination of the cowy odors in the milk. Therefore, either from the stand- 

 point of eliminating the germs, or from the standpoint of absorbing obnoxious 

 gases from the stable, the practice of exposing milk in the stable is reprehensible. 



X. STRAINING OF MILK. 



Too much energy is expended upon the straining of milk. Does it seem rational 

 to the milk producer that "it is possible for him to intercept germs which are 

 one ten-thousandth or one twenty-five thousandth of an inch in length by a copper 

 sieve with a one-sixteenth or a one-fortieth inch mesh; or by cheese-cloth, with 

 its loose texture, even M^hen used in folds four thick; or even by placing layers 

 of cotton over the sieve? One might pertinently ask the question, "Is it possible 



