EXPERIMENT STATION BULLETINS 



353 



Guinea pigs, Nos. 279 aud 280, were eacli inoculated intra-abdominally with 1 

 c. c. of the milk infected with tuberculoid material before it had been pasteurized. 



Both contracted general tuberculosis and showed marked lesions in the lungs, 

 liver and lymphatic glands. 



Guinea pigs, Nos. 273 and 275, from bottle 1, 274 and 276 from bottle 2, and 

 277 and 278 from bottle 3. were each inoculated intra-abdominally with 5 c. c. of the 

 infected milk after it had been pasteurized as above and when the controls 279 and 

 280 were examined, these animals were chloroformed and careful search made for 

 tuberculous lesions. None could be detected. These two methods are evidently 

 safe, because in each case the pasteurization killed the deadly virus. All the 

 animals died which received the infected milk before pasteurization and none of 

 the twelve which had received five times the amount of the pasteurized infected 

 milk showed any trace of tuberculosis. 



An apparatus which has been thoroughly tested and found to be efficient has 

 been devised for family pasteurization of milk and is here presented. This 

 apparatus, of course, assumed that the slightly cooked flavor and odor are not 

 objectionable. Instead of using water as the heating medium steam is employed 

 because of economy. 



This pasteurizing apparatus was suggested by Novy's laboratory pail st<^rili- 

 zer, and consists of a covered pail with a perforated bottom placed upon a water 

 bath provided with a shoulder to receive it. There is a hole in the cover so as 

 to provide for a continuous stream of steam. Inside the pail is a rack which holds 

 the bottles in position. The water bath is shallow and flanges out from the 

 shoulder. By this means a large heating surface is presented and the water is 

 soon raised to the boiling point upon the application of heat. 



To use the apparatus, the bottles of milk plugged with cotton wool are placed 

 in the rack inside the pail. While the water is reaching the boiling point, the pail 

 cover may be used to cover the water bath. As soon as the water boils, replace 

 the cover on the pail and then put the pail on the water bath. 



For household purposes, fifteen minutes of steaming will be sufficient; for infant 

 feeding, steam one-half hour. 



The milk in the bottles reaches 90° C. (194° F.) in five minutes, a temperature 

 that is beyond doubt in the destruction of pathogenic bacteria, even tlie tubercle 

 bacillus. The method is simple and needs little attention, and will answer every 

 purpose where milk and cream are to be used as such. The cooked flavor is f.o 

 slight when the pasteurization occupies only fifteen minutes that is may soon be 

 disregarded, unless there are digestive disorders caused by its constant use. 



Where cream is to be made into butter, the more careful method of pasteuriz- 

 ing at 68° C. (155° F.) is recommended, because the quality of butter is not 

 injured in the least. 



To pasteurize successfully every detail should be followed carefully in the right 

 spirit, otherwise the entire operation is worthless. Furthermore, each family 

 should attend to its own pasteurization, if safey is to be assured. There are 

 unscrupulous milkmen who advertise pasteurized milk without making much of 

 an effort to see that it is done as it should be. 

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