2l8 BACTERIA, YEASTS, AND MOLDS 



adopted in the larger cities, until it is possible to purchase 

 pasteurized milk in almost any large community. 



Pasteurization, to be really efficient, must be carefully done. 

 A lower temperature than 145° would be useless and indeed 

 sometimes might increase rather than decrease the numbers 

 of bacteria. One of the objections raised against the practice 

 is that in large dairy concerns the pasteurization is done 

 hastily and carelessly, so that the milk is injured rather than 

 benefited. To meet this objection various communities are 

 requiring that the pasteurizing apparatus and process shall 

 be under official supervision and control, thus insuring its 

 thoroughness. When pasteurization is carried out under 

 official inspection, the milk may be relied upon as safe. In 

 no other way can the public be guaranteed that its milk 

 supply may not spread contagious diseases. 



Two objections have been urged against pasteurized milk. 

 The first is that it has a tendency to encourage carelessness 

 in handling the milk. The dairyman might feel that since 

 the milk is to be pasteurized, it is not necessary for him to 

 be particularly careful in its production and handling, since 

 any bacteria that get into it will be subsequently killed. This 

 objection is met by the growing requirement that the milk 

 must reach a certain standard of cleanliness and freedom 

 from bacteria before it is submitted to pasteurization. 



A second widespread objection has been that pasteurized 

 milk is not quite so good a food as raw milk. This objec- 

 tion has been based chiefly upon the fact that pasteurization 

 as carried out in earlier years, at temperatures as high as 

 170° or more, did produce changes in the milk similar to 

 those produced by boiling, which rendered the milk less 

 easily assimilated by infants. This objection hardly holds 



