ACCURACY IlSr COMMERCIAL GRADING OF OPENED EGGS. 



13 



POSITION OF YOLK. 



When viewed before the candle the yolk of a perfectly fresh egg 

 is found to be located slightly above the meridian and is symmetrical 

 with the long axis of the egg. It is indistinct in outline and moves 

 very sluggishly as the egg is turned. As the egg ages the yolk appar- 

 ently becomes more opaque and may settle against the lowest part 

 of the shell. 



Of all the eggs studied 1,795, or 87.5 per cent, were eggs with free 

 yolks; 248, or 12.1 per cent, eggs with yolks settled close to the shell, 

 but not adhering; and 9, or 0.4 per cent, eggs in which the yolks 

 were either addled or adherent to the shell. Fewer eggs with adher- 

 ent yolks or addled contents are listed in Table VI, which gives the 

 results of examination of eggs graded by the candling method, than 

 are listed in Table V, where the eggs were graded out of the shell. 

 The reason for this is that eggs with slightly adherent yolks are often 

 difficult to detect by candling, especially if the shell is brown. 



These results confirm earlier studies ^ of similar eggs, in that they 

 show that a settled yolk is not in itself an indication that the egg 

 contains bacteria. 



Table .VI. — Relation of bacteria in eggs to position of yolk. 



I. EGGS CONTAINING BACTERIA. 



Position of yolk. . 



Num- 

 ber 

 ex- 

 am- 

 ined. 



Num- 

 ber 

 posi- 

 tive. 



Per 

 cent 

 posi- 

 tive. 



Free moving 



1,795 



248 



9 



241 

 32 

 5 



13.4 



Settled 



12.9 



Addled or adherent 



55 5 







Total 



2,052 



278 



13 5 







II. VARIATION IN BACTERIAL CONTENT OF EGGS CONTAINING BACTERIA. 





Number of bacteria per cc. 





Position of yolk. 



101 to 1,000. 



1,001 to 

 10,000. 



10,001 to 

 50,000. 



50,001 to 

 100,000. 



100,001 to 

 500,000. 



Over 

 500,000. 



Total 

 num- 

 ber of 





Num- 

 ber of 



eggs. 



Per 

 cent. 



Num- 

 ber of 

 eggs. 



Per 

 cent. 



Num- 

 ber of 

 eggs. 



Per 

 cent. 



Num- 

 ber of 

 eggs. 



Per 

 cent. 



Num- 

 ber of 



eggs. 



Per 

 cent. 



Num- 

 ber of 

 eggs. 



Per 

 cent. 



eggs. 



Free moving 



Settled.. . 



65 



10 



1 



27.0 

 31.2 

 20.0 



44 



18.3 



31 

 5 



12.9 

 15.6 



19 

 1 



7.8 

 3.1 



29 

 3 



12.0 

 9.4 



53 

 13 

 3 



22.0 

 40.6 

 60.0 



241 

 32 



Addled or adherent 



1 



20.0 



5 



















Total 



76 - --- 



45 





36 







20 





32 





69 





278 











1 U. S. Dept. Agr. Bui. 51, pp. 12, 30, 31. 



