PREPARATION/ OF FROZEN AND DRIED EGGS. 15 



COMPARATIVE STUDY IN TWO HOUSES ON EGGS BEFORE AND AFTER 



DESICCATION. 



The belt system used in E and F houses differed in some respects. In E house the 

 hot air entered the ducts in which the belts circulated through several flues and was 

 expelled through two others. In F house there was one inlet and one outlet for the 

 hot ail*. By the arrangement of the air ducts in E house the supply of air coming in 

 contact with the drying egg was replenished before it had become saturated with 

 moisture. The temperature of the intake air in E house varied from 135° F. to 160° F. 

 for whole egg, and in F house it was 160° F. for yolk and 140° F. for mixed egg. The 

 temperature of the outgoing air was about 10° lower in E house and about 30° lower 

 in F house than the incoming air. E house desiccated about 150 pounds of whole egg in 

 one hour and F house about 80 pounds. 



The belts of E house were considerably longer than those of F house; consequently 

 they were supported on the lower side by rollers. The portion of the egg on the belt 

 coming in contact with these rollers did not dry as quickly as the films of eggs on 

 the exposed sections of the belt. As a result, sticky masses, commercially termed 

 "wet lumps," were mixed with the flaky egg scraped from the belts. The imper- 

 fectly dried portions, however, represented but a small amount of the final product. 

 They were screened and subjected to further drying. The average moisture content 

 of the dried product immediately after being removed from the belts was at E house 

 8.82 for the whole egg. E house did not subject the dried egg to secondary drying. 

 F house, however, exposed the product to a temperature of 100° F. for about five 

 hours. The percentage of moisture then averaged 6.13 for the mixed egg and 5.04 

 for the yolks, as against 11.24 per cent for mixed egg and 11.21 per cent for yolk when 

 the dried egg was removed from the belts. 



BACTERIAL CONTENT. 



Eighteen comparative examinations were made of the product in E house before 

 and after desiccation. The results given in Table E- V (Appendix, p. 74) show in 

 practically every case (if the count of the dried product be divided by 3 to make it 

 comparable with the liquid egg) that there is a reduction in the number of bacteria 

 during the process of desiccation. 



The lowest count found in samples of the flaky dried egg, as shown in Table E-III 

 (Appendix, p. 70), was 65,000 per gram and the highest 20,000,000. The average 

 count for the 48 samples was 3,600,000. The number of B. coli varied from to 

 1,000,000 per gram. Only 6, or 12.5 per cent, contained 1,000,000. (Table E-VIII, 

 Appendix, p. 78.) 



The bacterial content of the samples of ' ' wet lumps ' ' averaged 6,900,000 and varied 

 from 1,100,000 to 18,000,000 per gram. Corresponding samples of flaky egg contained 

 between 430,000 and 12,000,000 organisms per gram (Table E-II) . Comparative results, 

 given in Table E-II (Appendix, p. 68), indicate that in some instances there is a 

 multiplication of organisms in wet lumps during the process of desiccation. There 

 was practically no difference in the bacterial content of wet lumps before and after 

 secondary drying. 



In the spring of the year there was practically no increase in the number of bac- 

 teria during drying. In the summer, however, there was appreciable multiplication 

 during desiccation (see Table F-I, Appendix, p. 80). This is undoubtedly due to 

 the warmer weather and the greater amount of water in the air during the summer. 



It is probable that an increase in the air supply to the belts and an increase and 

 rearrangement of the inlet and outlet ducts would facilitate desiccation and prevent 

 multiplication of bacteria without diminishing the solubility of the dried product. 



AMMONIACAL NITROGEN. 



The amount of ammoniacal nitrogen found in the desiccated products of E and F 

 houses is not comparable with the amount present in liquid egg before drying. For 

 example, the parallel tests given in Table E-V (Appendix, p. 74) showed that the 

 percentage of ammoniacal nitrogen calculated on the diy basis varied from 0.0073 to 

 0.0093 in the liquid egg and from 0.0009 to 0.0016 in the corresponding product after 

 desiccation. Similar variations can be seen in Tab] e F-VI (Appendix, p . 76) . These 

 results indicate that a portion of the ammoniacal nitrogen was volatilized during 

 desiccation. 



The amount of ammoniacal nitrogen volatilized from the product during desiccation 

 is not constant, according to the above tables. For instance, samples 41079 and 41085 

 listed in Table E-V contained 0.0093 per cent of loosely bound nitrogen in the liquid 

 form, but after desiccation one contained 0.0009 per cent and the other 0.0015 per cent. 

 Sincej therefore, the amount of loosely bound nitrogen lost from eggs during drying is 



