18 BULLETIN 224, U. S. DEPARTMENT OF AGRICULTURE. 



GENERAL SUMMARY OF LABORATORY RESULTS ON COMMERCIAL 



SAMPLES, 1912. 



The bacteriological and chemical findings of the data obtained from commercial 

 samples of liquid egg taken in D, E, and F houses during 1912 are summarized in 

 Tables 11 and 12 and shown graphically in figures 2, 3, and 4. 



The average number of bacteria per gram in the whites was 350,000, in the yolks 

 530,000, and in the whole and mixed eggs 1,800,000. The average amount of ammo- 

 niacal nitrogen on the dry basis was 0.0031 per cent in the whites, 0.0076 per cent in 

 the yolks, and 0.0074 per cent in the whole eggs. 



A comparison of these results shows that the average count of the whites is about 

 half that of the yolks, and that the latter contained approximately one-third as many 

 bacteria as the whole and mixed eggs. The antiseptic action of the white may ex- 

 plain its lower bacterial content as compared with that of the yolks, whole eggs, 

 and mixed eggs. It may be that the presence of soft eggs in the whole and mixed 

 eggs offers also an explanation of their higher bacterial content. 



WH/T£& ■ 350,000 

 YOLKS m -530,000 

 LEAK7M& EGGS ■ /,300,000 



WHOLE AND KM /o^nnoo 

 M/XEO EGGS I I / ' SOOOO ° 



SOET EGGS \20,000,000 



SECOND GffADE I I 3*000,000 



£TGOS 



7! %ggg S I I 7G,000,000 



Fig. 2. — Diagram showing average number of organisms per gram in commercial samples taken 

 in D, E ; and F houses in 1912. 



It is interesting to note that the average count of the product prepared from leaking 

 eggs is not far different from that of the whole and mixed eggs. The average count of 

 the former was 1,300,000 and of the latter 1,800, 000. l The amount of chemical de- 

 composition was no greater in the leaking eggs than in the whole and mixed egg. 



The product prepared from soft eggs graded as fit for food purposes contained de- 

 cidedly more bacteria than the whole or mixed egg, but the amounts of ammoniacal 

 nitrogen in the two were not so very far apart. The average number of organisms 

 in the soft eggs numbered 20,000,000 per gram, as compared with 1,800,000 in the 

 whole and mixed egg, whereas the percentage of loosely bound nitrogen averaged 

 0.0080 on the dry basis in the former and 0.0074 in the latter. The bacteria in the 

 soft eggs were not present in sufficient numbers or for a sufficient length of time to 

 effect a decomposition of the egg material. 



On the other hand, the second-grade frozen egg prepared from "beginning sours," 

 eggs with light-green whites, etc., and the tanners' egg were not only heavily in- 



1 Weighted average of bacterial content of whole and mixed eggs given in Table 11. 



