RELATION OF MICROORGANISMS TO SPECIAL DAIRY PRODUCTS 515 



If the cream from which the ice cream is made has been produced 

 and handled under sanitary conditions, the bacterial content should 

 consist chiefly of organisms of the Bact. lactis acidi type, in which case 

 the high count in the ice cream might not be objectionable. If, on 

 the other hand, the cream has been held in cold storage for some time 

 under conditions which inhibit the growth of the lactic organisms and 

 permit the development of putrefactive types, bacterial poisons may 

 be developed in the cream, which will be highly objectionable. There 

 seems to be little doubt that this is the cause of the cases of ptomain 

 poisoning, resulting from the use of ice cream. It is known that certain 

 types of bacteria, especially those belonging to the so-called putre- 

 factive group, are capable of developing at very low temperatures and 

 may, therefore, produce considerable quantities of toxic products in 

 the cream. Whether or not these products are developed before 

 the cream is manufactured or whether they may develop in the frozen 

 product cannot at present be stated. In general it can be said that the 

 total bacterial count does not indicate the wholesomeness of the ice 

 cream any more than does a similar count in buttermilk or in the com- 

 mercial fermented-milk drinks. The kinds of organisms present is a 

 far more important question from the standpoint of the wholesomeness 

 of the ice cream. However, the results obtained by many ice-cream 

 manufacturers have demonstrated the fact that the germ content of this 

 product can be quite definitely controlled by the same methods of care 

 and sanitation as are required in the handling of other forms of dairy 

 products. 



