56 BULLETIN 51, U. S. DEPARTMENT OF AGEICULTURE. 



BLACK ROTS. 



Black rots receive their name from the black appearance which 

 they present before the candle. Out of the shell they are a homo- 

 geneous olive green liquid with an offensive odor resembling that 

 of hj^drogen sulphid. It is often possible to pick out a black rot 

 from receipts bj^ the odor and grayish tint of the shell. The results 

 of two samples consisting of from four to eight of these rots showed 

 counts of more than a billion bacteria and an amount of ammoniacal 

 nitrogen much greater than that found in any previous type of egg 

 discussed (see Table 25), Black rots, therefore, represent eggs in 

 the last stages of decomposition. Their only value is for fertilizer 

 purposes. 



Table 25. — Small samples of Tjlaclc rots. 



Sample 

 No. 



Source. 



Date of 

 collec- 

 tion. 



Number of bacteria per 

 gram at — 



Number 

 of gas-pro- 

 ducing 

 bacteria 

 per gram 



in lac- 

 tose bUe. 



Gelatin 

 liquefy- 

 ing or- 

 ganisms 

 per gram. 



Percentage 

 of ammon- 

 iacal nitro- 

 gen, Folin 

 method. 



Per 



cent 



of 



mois- 



Size of 

 sample. 





20° C. 



37° C. 



Wet 



basis. 



Dry 



basis. 



ture. 





4421 



D2 

 Do 



1912. 

 May 28 

 July 31 



1.100,000.000 

 •2,.300.000.000 



310.000.000 



10.000.000 



99,000,000 







72.31 

 71.40 



4 eggs. 

 8 eggs. 



4873 



2.300.000.000 lo.ooo.onn 



0. 0229 



0.0800 











DETERIORATED EGGS NOT DISTINGUISHABLE BY CANDLING. 



The eggs previously discussed have been recognizable before the 

 candle or distinguishable b}^ other characteristics, such as dirty or 

 cracked shells. Some eggs, however, which are distinctly undesir- 

 able, can not be detected b}" candling and must be eliminated by the 

 breaker. These are recognized when out of the shell b}^ color, odor, 

 or general appearance. The great majority of them belong to three 

 groups : Eggs having a green white, often called " grass " eggs by 

 the trade ; eggs having a pungent, characteristic odor, commonly 

 known as " sour " ; and eggs which are " musty," that is, having an 

 odor which is exceedingly penetrating, verj^ characteristic, and often 

 suggesting that of the common jirnson weed. This odor increases 

 when heat is applied, so that a single musty egg in 100 pounds of 

 good egg will spoil it for bakers' purposes. 



A number of eggs have distinctive odors when out of the shell, 

 though there may be no visible signs of deterioration. Sometimes 

 the eggs absorb these odors, such as the fruit}^ odor which comes when 

 eggs and apples are held in a closed space together, or that of straw- 

 board from the fillers in which they are packed. Unless these ab- 

 sorbed odors carry with them an objectionable taste there would seem 

 to be no reason for discarding the eggs. Other odors, apparently 



