12 



BULLETIN 944, U. S. DEPARTMENT OF AGRICULTURE. 



factory pan. When this was found necessary the milk was cooled 

 to a very low temperature and held in that condition overnight; 

 only a verj^ slight increase in acidity was shown. 



The evaporated milk from each run was standardized to show 

 close to 18.15 per cent solids not fat. The samples from the raw 

 milk showing no coagulation with alcohol were standardized to show 

 slightly above this figure. All samples were sterilized in one of the 

 large Fort Wayne sterilizers used regularly by the condensery. 



Four trials of grading and condensing milk on a commercial basis 

 were made in this factory. The evaporated milk from the raw milks 

 showing no coagulation with alcohol in all cases came through the 

 sterilization process in fine shape, producing no curdiness and indi- 

 cating that they would have stood more heat ; in all four cases, also, 

 the evaporated milk from raw milks showing coagulation with 

 alcohol gave a pronounced curdiness that could not be removed by 

 prolonged shaking. 



Table 4. — Results obtained by grading ivith the alcohol test at Factory B. 



Raw milk. 



Acidity. 



Reaction 

 to alco- 

 hol. 



Solids 

 not fat 

 in evap- 

 orated 

 milk. 



Steriliza- 

 tion o f 

 evaporat- 

 ed milk. 



Batch 

 No. 



Weight. 



1 

 2 

 3 



4 

 5 

 6 



7 

 8 



Pounds. 

 12,400 



4,250 

 10,100 



9,100 

 11,500 



9,100 

 12,400 



6.300 



Per cent. 

 0.140 

 .170 

 .150 

 .175 

 .165 

 .175 

 .145 

 .160 



4. 



+ 

 + 

 + 



Per cent. 

 17.96 

 17.06 

 18.53 

 18.16 

 18.24 

 18.16 

 18.25 

 17.91 



No curd. 

 Curdy. 

 No curd. 

 Curdy. 

 No curd. 

 Curdy. 

 No curd. 

 Cardy. 



Table 4 gives the data on the four trials of grading and condens- 

 ing at this establishment. The titratable acidity of the lots of milk 

 showing coagulation with alcohol is somewhat higher than that of the 

 milk showing no coagulation with alcohol. We have no definite 

 data that will enable us to say this difference in acidity would ac- 

 count for the difference in coagulation. In order to throw some 

 light on this question, four cans of the sterilized milk were sent to 

 the laboratory where the h}- drogen-ion concentration or true acidity 

 was determined with the following results : 3 



Lot. pH. 



5 5.96 



6 5.80 



7 5.90 



8 5.84 



3 The determinations were made by II. F. Zoller, of the Dairy Division. 



