EXPERIMENT STATION BULLETINS. 483 



made. This count was used un'til a new s'Mpment was received. Enough 

 gelaitin wais ordered eaich time to laist from four to eight weebs. The bac- 

 terial count ranged from 850,000 to 4,000,000 per cubic centimeter with an 

 aveii'age of 2,500,000 per cubic centimeter. The gelaitin was added just 

 before pasteurizatiou in the powdei'ed form. 



THE INFLUENCE OF PASTEURIZATION UPON THE BACTERIAL CONTENT OF 



THE ICE CREAM MIX 



The next step in the manufacturing process is the mixing of the raw 

 products and sitandardization of the mix. The mix is then pasteurized. 

 The raw prodcts as was shown in TaWe I contained large numbers of 

 bacteria. When the products were mixed together they istili contained 

 large numbers as is shown in Table II. Pasteurizatiou as carried out at 

 this factory was at 65.6° C (150° F) for 30 minutes. The type of pas- 

 teurizer used was a 500 gallon glass-lined Elyria type. 



The data ishowing the influence of pasteairization of the mix on the 

 bacterial content are presented in Table II. The percentage decreases in 

 the number of bacteria due to pasteurization varied from 94.5 per cent 

 to 99.9 per cent. The average per cent decrease being 98.97. The above 

 data ishould leave no doubt in the mind of any one as to the value of pas- 

 teurization ais a means of reducing the numlber of bacteria in the ice 

 cream mix. 



