DETERMINING QUALITY OF MILK FOR CONDENSERIES. 



9 



that showed curdiness after sterilization and shaking, while it would 

 have rejected 2 out of 44 that were all right ; that is, showed no 

 curdiness. The acid test would have rejected 18 of the 46 samples 

 showing curdiness after sterilization and shaking, while it would 

 have rejected 21 of the 44 that showed no curdiness. 



The following tabulation shows the percentage of satisfactory and 

 unsatisfactory milk samples that would have been retained or re- 

 jected by the alcohol and acidity tests : 



Alcohol test. Acidity test. 

 (Percent.) (Percent.) 



Satisfactory milk samples retained 95. 5 52. 3 



Satisfactory milk samples rejected 4. 5 47. 7 



Unsatisfactory milk samples retained 6. 5 60. 9 



Unsatisfactory milk samples rejected 93. 5 39. 1 



Table 2 gives a more concrete comparison of the relative value of 

 the alcohol and acid tests in the work done at Grove City, Pa. 



Table 2. — Relative value of alcohol and acidity tests on samples run at Grove 



City, Pa. 





Kind of samples. 



Number 

 of sam- 

 ples. 



Alcohol test. 



Acidity test. 





Times 

 correct. 



Times 

 incorrect. 



Times 

 correct. 



Times 

 incorrect. 





44 

 46 



42 

 43 



2 

 3 



21 

 18 



23 





28 









Total 



90 



100 



85 

 94.4 



5 

 5.6 



39 

 43.3 



51 





56.7 









EXPERIMENTS AT CONDENSERIES. 



WORK AT FACTORY A. 



Realizing the importance of trying out the alcohol test under other, 

 including commercial, conditions, the work was extended to a con- 

 densery, which is designated as Factory A, 2 where considerable diffi- 

 culty had been experienced in making an evaporated milk meeting 

 the requirements of 26.15 per cent total solids and 8 per cent fat. 

 The small laboratory apparatus used in the Grove City work was 

 set up in the laboratory of this plant and work of the same nature 

 as that done at Grove City carried on. Samples of individual pat- 

 rons' milk showing positive or negative reaction with alcohol were 

 condensed to bring the product as nearly as possible to 18.15 per cent 

 solids not fat, that being the portion of the evaporated milk causing 

 the difficulty in sterilization. It was the aim to have the samples 

 that were evaporated from raw milk showing no coagulation with 

 alcohol slightly above the point of 18.15 per cent solids not fat, and 



2 The assistance of F. B. Evans in the work at this factory is acknowledged. 



