The Microbial Flora of Graded Cream. 73 



from those of the previous year's work, the same conclusions 

 can be drawn. The results indicate either that the proposed 

 method of grading does not determine the true quality of the 

 cream, or that the microbial flora of cream has no influence on 

 the quality. In order to determine which of these conclusions 

 was correct the data obtained from these 135 cream samples 

 were resummarized by classifying the samples into first- and 

 second-grade cream according to the following methods : (1) on 

 a 0.55 percent acidity basis ; (2) on a 0.6 percent acidity basis, 

 and (3) by flavor and odor. The results obtained by using the 

 increased basis — that is 0.55 percent and 0.6 percent — are 

 found summarized in tables 5, 6, 7 and 8, respectively, and are 

 self-explanatory. A complete record of the forty-four samples 

 analyzed the previous year was not available for reclassifying. 



Table 5. 



Summary of the different types of microorganisms observed in 135 samples of cream when graded 

 into first- and second-grade cream by 0.55 percent acid. 



Type. 



Lactic acid type 

 Neutral type . . . 

 Liquefying type 

 Colon group . . . , 

 Yeasts 



Number per cubic centimeter. 



First-grade cream. Second-grade cream. 



270,000,000 



113,000,000 



2,100,000 



500 , 000 



700,000 



243,000,000 



47,000,000 



2,700,000 



500,000 



400,000 



Table 6. 



Table 7. 



Summary of the different types of microorganisms observed in 135 samples of cream when graded 

 as first- and second-grade cream by 0.6 percent acid. 



