CHAPTER VIII 



PASTEURIZATION 



Pasteurization of milk consists in heating the milk 

 at various temperatures below boiling for a variable 

 period of time. The term pasteurized milk is very indefi- 

 nite in its meaning because the process is not always car- 

 ried out in the same manner, but since 1913, when the 

 Commission on Milk Standards of the New York Milk 

 Committee published its second report, there has been 

 more uniformity in this country than formerly with re- 

 gard to temperature and time of exposure, state and 

 local authorities having very generally accepted the 

 standard adopted by the Commission. This standard 

 specifies 140 to 155 F. (60 to 68 C.) as the minimum 

 temperature at which the milk shall be heated, the mini- 

 mum period of exposure to be 20 minutes at 140 F. 

 (60 C.), with one minute less for each degree of tem- 

 perature above 140 F. But, at the same time, in order 

 to allow for the variations in temperature and holding- 

 time which may occur under commercial conditions, the 

 Commission recommended that the milk be heated to 

 at least 145 F. (62.8 C.) for at least 30 minutes. In 

 Europe, pasteurized milk is usually milk which has been 

 heated for a few moments at 176 F. (80 C.) or above, 

 although within recent years the method of heating the 

 milk at a lower temperature for a longer period has 

 been adopted to some extent. 



When the first commercial milk pasteurizer was in- 

 troduced into this country in 1895, pasteurization was 

 recommended to milk distributers as a means of pre- 

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