BACTERIOLOGICAL DATA ON FRESH EGGS. 21 



infected material or injected according to various methods. Only 

 normal, healthy animals should be used, and they should be prop- 

 erly identified, weighed, and careful notes made as to their behavior 

 subsequent to inoculation. 



BACTERIOLOGICAL DATA ON FRESH EGGS. 

 PROCEDURE. 



The strictly fresh eggs examined were of a known origin, no egg 

 being more than one day old; they were laid under good conditions 

 and handled in a cleanly manner. The shells were broken on the 

 edge of a sterile Petri dish, and in a number of instances the whites 

 were separated from the yolks at the time of breaking by pouring the 

 egg from one half .of the shell fo the other, in the same manner as 

 would the housewife, each portion being placed in sterile dishes for 

 analysis. No unusual precautions were observed in breaking the 

 eggs, 1 other than the use of sterile containers for the reception of 

 samples. In removing portions of the egg substance for examination 

 only large-caliber pipettes were used to make dilutions, as great diffi- 

 culty was experienced in attempting to use the ordinary pipette with 

 small openings. One cubic centimeter quantities were used for 

 analysis instead of weighing 1 gram of the substance, that the results 

 might be expressed on the whole cubic centimeter basis, instead of 

 beginning with 0.1 gram of the material. The eggs having no 

 bacteria in 1 cc of the egg substance examined are considered bacterio- 

 logically sterile. The absence or presence of strictly anaerobic organ- 

 isms was determined by dextrose shake agar cultures. 



For the determination of B. coli the lactose-peptone-ox-bile 

 medium was used, and the bacterial count was made after three to 

 four days incubation on plain agar, according to the previously 

 outlined methods of examination. 



DETAILED DATA OBTAINED. 



It will be seen by studying Table 1 that the egg albumen from these 

 strictly fresh eggs contained fewer bacteria than did an equal volume 

 of the egg yolk; and that more of the albumen samples were sterile 

 than were the corresponding samples of yolks separated from the 

 same eggs. Similar results were obtained on the few samples of fresh 

 egg yolks and whites reported in Bulletin 115, Bureau of Chemistry. 2 

 In her study on fresh eggs of a known grade M. E. Pennington 3 has 

 shown that such eggs contain few if any bacteria, and B. coli was not 

 found in the 57 experiments made, including approximately 150 eggs. 



1 U. S. Dept. Agr. Bureau of Chemistry Bui. 115. Effect of Cold Storage on Eggs, Quail, and Chickens, 

 by Wiley, Pennington, Stiles, Howard, and Cook. 

 > Loc. cit. 

 s A chemical and bacteriological study of fresh eggs J. Riol. Chem., 1910, 7 (2): 109. 



