PREPARATION OP FROZE 1ST AND DRIED EGGS. 23 



side of the room from the beginning of the work in the mor ning until noontime, when 

 it was removed to the freezer; and again, from the beginning of the afternoon until 

 the close of the day, when a second trip was made to the freezer. 



The yolks were put into a 40-quart milk can. This at noontime and again at night 

 was emptied into a large straight-sided can provided with an ordinary creamery fau- 

 cet. The yolk was poured into this churn through a large mesh wire sieve to remove 

 scraps of eggshell. It was then stirred with a paddle in the churn until the yolks 

 were thoroughly broken and mixed, or the whites and yolks of the whole eggs made 

 into a uniform liquid. The containers were then placed below the faucet of the 

 churn and the egg run into them. The churn was washed at noontime after it was 

 used and again at night. 



The eggs were chilled before breaking, but their long wait after removal from the 

 shell in this hot room effectually undid the good which previous chilling does to a 

 perishable product. 



Sources of Bacterial Contamination. 



In order to determine the bacterial cleanliness of this method and equipment, each 

 obvious factor was tested by laboratory methods for the amount of contamination. 



Plate I, figure 1, represents the number of colonies which developed on a 4-inch 

 petri plate from one drop of water taken from the saucer after throwing away a bad egg 

 and washing in running hot water. It is obvious, from the large number of colonies 

 developing, that this method of cleaning the receiver is not sufficient to remove the 

 organisms furnished by the undesirable egg. Plate I, figure 2, shows the number of 

 bacteria in one drop of water which had collected on the shelf holding the wet saucer. 

 Here, again, is a rich source of bacterial contamination of the final product. As one 

 would expect, there are many more organisms in this drop of drip than were obtained 

 from the saucer itself. 



The picture of the breaking equipment shows a shallow metal tray that was placed 

 under the egg pails for the sake of cleanliness. This tray gradually collected drippings 

 of water from the saucer and its shelf and of egg which ran down the sides of the pails 

 when their contents were emptied into the milk can; consequently, there were even 

 more organisms in the liquid that accumulated in the tray than there were on either 

 the saucer or the shelf, and when the pails were emptied this liquid sometimes dropped 

 into the final receiver. One drop of it was examined with the result shown in Plate I, 

 figure 3. The organisms as they developed on a 4-inch petri plate were so numerous 

 that it was impossible to distinguish them as individual colonies. Each step of this 

 process added more and more bacteria to the product, though as carried out it was 

 even cleaner than the usual kitchen methods. The breaker had no means of detecting 

 either the source or the amount of the infection that his routine caused. 



The bacteria on finger tips wet with egg are shown in Plate I, figure 4. To obtain 

 this preparation, the breaker touched her five wet finger tips against the bottom of a 

 dry, sterile petri plate. Agar was then poured in, shaken to distribute the organisms 

 evenly, and incubation allowed to proceed. The results indicate that the hands of 

 the egg breaker are also a source of infection which, if possible, must be overcome. 



Comparison op the Commercial Product with Experimental Samples. 



This house did not buy eggs especially for breaking, but used breaking stock sorted 

 from their current receipts. The supply of eggs going to the breaker while the house 

 was under observation was of exceptionally good quality. The bacterial count and 

 chemical analysis of eight samples, including whole egg, yolks and whites, are given 

 in Table 13, Part I. The odor and appearance of all the samples were excellent. 

 The amount of loosely bound nitrogen is low, indicating that, in the shell at least, 

 the eggs were of good quality. But the number of bacteria in the final product 

 shows a wide variation, which can not, apparently, be attributed to the eggs. The 

 minimum count for egg white is less than 1,000, and the maximum is 6,500,000 per 

 gram; the minimum for yolks is 2,000,000 and the maximum is 4,800,000 per gram. 

 The number of presumptive B. coli varied from 100 to 100,000 per gram. 



An effort was made to eliminate the sources of contamination already described by 

 modifying the equipment and more effectually cleaning the apparatus soiled by eggs 

 that were discarded. Instead of the apparatus in use in this house, there was sub- 

 stituted the breaking outfit pictured and described on page 11 of Circular 98, Bureau 

 of Chemistry, United States Department of Agriculture. Trays holding pails for 

 liquid egg were discarded. Tissue paper was provided on which to dry finger tips. 

 Pails and cans, such as were commonly used, were retained; but all were washed in 

 water at 160° F. and held in that water for five minutes or steamed. 



