EFFECT OF DEHYDRATION UPON THE BACTERIAL 
FLORA OF EGGS 1 
By George G. De Bord 
Microbiological Laboratory , Bureau of Chemistry , United States Department of 
Agriculture 2 
INTRODUCTION 
The commercial dehydration of broken-out eggs has been devel¬ 
oped to minimize the losses incident to shipment and storage where 
long distances and long periods of time are involved. The reduction 
in volume and weight alone is significant, but the reduction in the 
demands on cold-storage facilities and the need for expensive and 
elaborate packing methods is still more important. Dehydration has 
made possible the development of large egg-handling establishments 
in China, which at present supply most of the dried egg used by the 
baking industry in the United States. 
Sound fresh eggs subjected to one of the controlled drying processes 
make a very desirable dried product. The practices involved in the 
breaking and mixing of large quantities of commercial eggs, how¬ 
ever, introduce so many opportunities for spoilage and contamina¬ 
tion that a bacterial examination of the number and character of the 
bacteria, and a study of the opportunities for the growth of the micro¬ 
organisms, seem desirable. Bacterial findings must be correlated 
with the odor, taste, or other evidence of soundness or spoilage in 
the manufactured product, and with the same properties in the raw 
materials. 
Sources of contamination during dehydration are the hands of the 
operator, the apparatus, dirt from the air or from the surface of the 
shell, and the fragments of shell unavoidably left in the product. 3 
Perhaps the principal source is the occasional single egg which con¬ 
tains large numbers of bacteria but has not developed physical 
evidence of spoilage by odor or taste. Such eggs have been found 
and reported in the investigations of Jenkins and Hendrickson. 4 
Also, many eggs which have been damaged in handling become con¬ 
taminated with microorganisms in considerable numbers before evi¬ 
dence of decomposition is noticeable. Therefore, a mixed product 
selected as sound by physical examination may at times contain a 
large number of bacteria per cubic centimeter. It seems fair to 
assume that a great many bacteria may be introduced without there 
having been negligence or gross carelessness in the preparation of 
the original mix. 
With such initial bacterial contamination, enormous numbers of 
bacteria will develop in a comparatively short time, if the mix is 
1 Received for publication Oct. 28, 1924; issued September, 1925. 
2 This investigation was a part of a bacteriological and chemical study of dried eggs conducted in co¬ 
operation with H. W. Redfield, G. C. Swan, and H. I. Macomber. Acknowledgment is due Charles 
Thom for many suggestions. 
a Pennington, M. E., Jenkinson, M. K., Stocking, W. A., Ross, S. H., St. John, E. Q., Hen¬ 
drickson. N., and Hicks, W. B. a study of the preparation of frozen and dried eggs in the 
producing section. U. S. Dept. Agr. Bui. 224, 99 p., illus. 1916. 
4 Jenkins, M. K., and Hendrickson, N. accuracy in commercial grading of opened eggs. U. S. 
Dept. Agr. Bui. 391, 27 p., illus. 1918. 
Journal of Agricultural Research, 
Washington, D. C. 
Vol. XXXI, No. 2 
July 15,1925 
Key No. E-32 
( 155 ) 
LIBRARY 
CEREAL INVESTIGATION! 
