PASTEURIZATION 219 
of the heat from the hot milk before the latter reaches 
the cooler. (See Fig. 27.) In the “holder” method, the 
milk is run from the pasteurizer or heater into the holder 
or retarder to be held at a certain temperature for a 
certain period of time. In the holder, the milk stops 
COLD RAW 
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hel PASTEURIZED 
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GUTLET FOR COLO 
PASTEURIZED PER 
Fie. 27.—Regenerative Cooler. (B.A. I. Cire. 184). 
flowing and is actually held for the required time. On 
the other hand, in the retarder the flow continues, but is 
slowed or retarded sufficiently to hold the milk for the 
required period. The retarder is not as reliable as the 
holder. A simple and cheap holding tank is shown in 
