424 



ENGINEERING ASPECTS OF PASTEURIZATION 



by this method reduced the cream volume on the bottled milk so that many of the 

 dealers themselves became dissatisfied with flash pasteurization. 



Practically any type of milk heater, such as the Danish or centrifugal heater, 

 the barrel heater, or the tubular heater, can be used for flash pasteurizing (see Fig.4). 

 The use of a temperature controller insures more even heating of the milk and 

 eliminates thenecessity of controlling the hot water or steam, used a3 the heating me- 

 dium, by hand-operated vah-es. 



Fig. 5. — Electric-flash pasteurizer (three units); regenerative heater cooler, filter, electrical 

 hcatins chamber. 



The treatment of milk by an electrical method, known as "electropure," is essen- 

 tially flash pasteurization, using electricity for part of the heating. The raw milk is 

 pumped through a regenerative heater-cooler, bringing it up to about 120° F., through 

 a filter and into an electrical heating chamber in which electricity passes through the 

 milk and heats it by resistance to about 160° F. (see Fig. 5). The treated milk then 

 passes over the outside of the regenerative heater-cooler and over a second section 

 of cooler using brine. An electrical thermostatic temperature-controller is provided 

 with the bulb located in the outlet pipe from the electrical heating chamber. 



PASTEURIZATION DEFECTS AND THEIR CORRECTION 



The tremendous benefit of pasteurization of milk to the public health is generally 

 recognized. It has been the greatest single factor in the prevention of thousands of 



