UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 391 



Contribution from the Bureau of Chemistry 

 CARL L. ALSBERG, Chief 





Washington, D. C. 



PROFESSIONAL PAPER 



December 10, 1918 



ACCURACY IN COMMERCIAL GRADING OF 

 OPENED EGGS. 



By M. K. Jenkins, Assistant Bacteriologist, and Norman Hendrickson, Assistant 

 Chemist, Food Research Laboratory. 



CONTENTS. 



Page. 



Introduction 1 



Purjiose, plan, and extent of investigation. . . 2 



History and bacterial content of samples 4 



Eflect of condition of shell on bacterial con- 

 tent of egg 6 



Relation between number of bacteria and 



phiysical condition of the egg contents 11 



Descriptions and bacterial counts of eggs 



graded out of the shell 14 



Effect of contaminated eggs upon composite 



products 18 



Eggs rejected during grading 21 



Summary 25 



INTRODUCTION. 



The quality of liquid egg used in making frozen or dried egg 

 products depends upon two factors: First, the character of the eggs 

 entering tlie product; and, second, the cleanliness of preparation. 

 Eggs, good and bad, as they appear before the candle and out of the 

 shell, with their respective chemical and bacterial characteristics, 

 have been discussed in Bulletin 51.^ The precautions necessary to 

 insure cleanhness when opening the eggs and collecting their con- 

 tents to be frozen or dried have been discussed in Bulletin 224,^ in 

 which pubhcation much attention is directed also to the character 

 of the eggs used. During the progress of the work the question of 

 the accuracy of grading eggs by sight, smell, and taste frequently 

 arose. It was observed that samples made from comparatively 

 high-grade stock sometimes had a higher bacterial content than 

 could be accounted for on the basis of faulty manipulation. They 

 seldom showed chemical evidence of decomposition. It was ob- 



1 A Bacteriological and Chemical Study of Commercial Eggs in the Producing Districts of the Central 

 West. U. S. Dept.Agr. Bui. 51, 77p., 8pl.,2flg., .Tuly20, 1914. 



2 A Study of the Preparation of Frozen and Dried Eggs in the Producing Section. U. S. Dept. Agr. 

 Bui. 224, 99 p., 17 pi., 7 fig., Apr. 28, 1916. 



62492°— BuU. 391—18 1 



