PASTEURIZING MILK. 7 



wash the bottles thoroughly in order to remove the barium solution. 

 Care must also be exercised to keep the chlorid solution from all 

 edible products about the plant. 



ADVANTAGES AND DISADVANTAGES OF PASTEURIZATION IN 



BOTTLES. 



From a bacteriological standpoint the advantage of pasteuriza- 

 tion in bottles lies in the fact that reinfection after pasteurization is 

 usually prevented. In the ordinary methods of pasteurization there 

 is a great opportunity for infection from coolers and in bottling. Of 

 course the proper handling in the ordinary method of pasteurization 

 reduces and may prevent subsequent reinfection, but the possibility 

 still remains. 



It is the general opinion that the process of pasteurization in bot- 

 tles also effects a great saving in milk by doing away with the loss 

 in evaporation over the coolers and with the loss in milk which 

 adheres to the apparatus in the process of pasteurization. Undoubt- 

 edly this saving is quite a considerable factor. There may also be a 

 saving in the expense of machinery and in the interest on the capital 

 invested, but it is not the province of this paper to discuss the finan- 

 cial aspect of this process. 



On the other hand, in a plant where pasteurization is now per- 

 formed in the ordinary way, it would be necessary to install an 

 entirely new equipment for this system of pasteurization in the 

 bottle. When bottles are heated and cooled by submerging in water 

 perhaps the greatest disadvantage is the cost of water-tight caps. 

 This item of expense is important, since it may increase the cost of 

 pasteurization as much as one-fifth of a cent per bottle. Whether 

 the saving in milk losses is sufficient to overcome this added expense 

 can be determined only by the actual operation of a milk plant. In 

 some processes of pasteurization in the bottle ordinary caps can be 

 used, as the bottles of milk are heated and cooled by a spray of water, 

 and the tops of the bottles are protected by metal coverings. 



MACHINERY FOR PASTEURIZING MILK IN BOTTLES. 



Pasteurization in the bottle has been practiced on a commercial 

 scale in many different ways since water-tight caps made it possible 

 to heat milk in bottles by submerging in water. When this process 

 of pasteurization was first practiced the bottles, with water-tight 

 caps, were placed in tanks and heated, held, and cooled by changing 

 the water. This method, while satisfactory on a small scale, was 

 hardly practical in large plants. Several types of machines have 

 been invented, which make the process continuous. One of these 



