12 A BACTERIOLOGICAL STUDY OF EGGS. 



especially true of "musty" and "sour" eggs, -which cause some of 

 the difficulties experienced in the trade. 



It is in summer, during the egg-breaking season, that the largest 

 percentage of inferior eggs escapes the candlers. Should they pass 

 the breakers also, to be manufactured into frozen or dried egg prod- 

 ucts, they become a portion of the finished article. "Black rots" 

 and large "blood rings," the more advanced types of spot eggs, are 

 usually distinguished without difficulty by candling, but certain 

 kinds of spots may escape detection. 



(1) Firsts and extras. This grade includes all freshly laid, sound, 

 whole, clean shell, medium, and good-sized eggs. The best eggs of 

 the year are laid during the spring months, and it is this grade which 

 is usually selected for storage, to be removed some months later for 

 the winter trade. The extras are selected from this grade to suit 

 local demands of the city in which the eggs are to be sold. For 

 example, a large, clean shell, whole, brown egg would be selected for 

 markets in the vicinity of Boston, while on the other hand a large, 

 clean shell, whole, white egg would be preferable for New York 

 markets, the quality of the goods being the same in each case. 



(2) Seconds. Into this group enter all the grades not included 

 under firsts, except the "spots" and "rots." This group may be 

 further subdivided into others. Generally this grade contains all 

 the under size, dirty, checked, cracked shell, or weak eggs, which 

 could not be classed as firsts: 



(a) Undersized: Eggs which may be classed as firsts except for 

 their size. 



(b) Checks and cracks: Eggs the shells of which have become 

 broken by careless handling but which have intact shell membranes. 



(c) Leakers: Eggs whose shells and shell membranes are suffi- 

 ciently broken to permit a portion of their contents to escape. 



(d) Dirties: Eggs the shells of which have become soiled from 

 unclean nests, etc. 



(e) Weak eggs : In this grade are placed all eggs in which the albu- 

 men has become weak or watery due to high or varying temperature 

 changes. 



All of the above-mentioned grades are considered to be suitable 

 for food purposes when handled under proper conditions, except 

 the leakers, which are generally badly contaminated. 



(3) Spots and rots. This grade comprises all of the discards and 

 is considered useful only for manufacturing purposes, such as for 

 tanning leather, etc. 1 They are eggs which show a spot before the 

 candle. These spots may be due to developing embryos, blood 

 rings, or molds, and the attachment of the yolk to the shell which 

 may be caused by holding in one position. 



i Rosenberger, Randle C. A study of eggs offered for sale as pure food. New York Medical Journal, 

 1910, 92 (27): 1313. 



