2 BULLETIN 391^ U. S. DEPARTMENT OF AGBICULTURE. 



served, also, that the lower the grade of the breaking-stock , eggs 

 and the more numerous the discards in the breaking room, the higher 

 was the average bacterial count, even though every care was used by 

 the breaker to ehminate unfit eggs. Apparently, then, there are some 

 infected eggs among the cracked eggs, dirty eggs, and stale seconds, 

 which so often go to the egg-breaking plant, which it is either quite 

 impossible or very difficult to detect when grading out of the shell 

 by ordinary means. The questions now to be considered are: What 

 is the character of these eggs, how many bacteria do they contain, 

 and how frequently do they occur ? ^ 



PURPOSE, PLAN, AND EXTENT OF INVESTIGATION. 



PURPOSE. 



The purpose of the investigation was fourfold: 



1. To obtain additional information regarding the bacteriology of 

 individual eggs used in the preparation of frozen and dried eggs. 



2. To determine the accuracy of the present methods of grading 

 individual eggs. 



3. To find the number and kinds of eggs containing bacteria not 

 detected by the usual grading. 



4. To determine the effect of eggs containing bacteria upon com- 

 posite products as- evidenced by the bacterial content and the 

 amount of ammoniacal nitrogen present in the finished product. 



PLAN. 



The material for study consisted of breaking stock — that is, odd- 

 sized eggs, dirty eggs, cracked eggs, shrunken eggs, and heated eggs. 

 The samples were made up of approxima'tely six dozen eggs each and 

 were purchased in all but a few instances from commission houses 

 located in a large eastern consuming center. 



All of the eggs for the experiments were commercially candled 

 by the regular candlers of the commission house, who aimed to 

 reject as unfit for food purposes all eggs containing blood, either in 

 the form of clots or blood rings, all eggs with either broken or ad- 

 .herent yolks, and all addled eggs, and to retain eggs with whole yolks 

 freely moving in the white. Eggs showing signs of incubation prior 

 to the appearance of the blood ring were not discarded. 



On receipt at the laboratory each egg in the sample was numbered 

 and described fully. The color, cleanliness, and soimdness of the 

 shell were noted. The eggs were recandled and the condition of 

 the white and yolk observed. They were then opened asepticaUy 

 and placed individually into sterile glass custard cups similar to 



1 The work discussed in this bulletin was done under the direction of Dr. M. E. Pennington, to whom 

 thanks are due for many valuable suggestions. A large part of the routine bacteriological work was done 

 by Dr. E. Q. St. John and Dr. E. Witmer, and the chemical work was performed by E. L. Connolly. 



