top view should be then gently pushed over on their sides, and again the eggs with
stained or dirty shells should be removed or candled. These two operations will remove
all dirty or stained eggs that are noticed at first glance.
b. The remaining eggs of the trays should be removed, two eggs in each hand,
for candling. On the way to the candling light, the eggs in each hand should be rotated
under the rays of a light that illuminates the contents of the sample. As the eggs are
rotated, the shell should be observed for stains
or dirty conditions.
c. This operation (rotation and observation for dirt) should be performed rapidly
enough so that the motion of the hand from the case light to the candling light is made
in one sweeping motion. Any stained or dirty eggs which are detected at this point
should be candled and segregated before the candling of clean eggs is begun. When
the eggs are placed before the candling light, previously undetected eggs with dirty or
stained shells should be removed. The grader should always have clean, dry hands to
avoid staining the shells. The candling aperture should be of a material that will not
mark or stain the shell and will aid in minimizing breakage.
d. In machine mass candling, the examination for cleanliness is most often done
on the conveyor when vacuum lifts are used or by the person putting the eggs on the
receiving apparatus. This operation should be in a well lighted area, and it is preferable
to have sufficient lighting directly over the conveyor and case, for ease of examination.
The obvious stains or dirties can be removed directly from the case prior to transfer to
the machine or they may be picked from the conveyor system, if this is used. This will
depend on whichever is the most efficient method. This method of removal of soiled
eggs can be very efficient if the operator has sufficient time to carefully observe the
CLASSIFICATION OF SHELL CLEANLINESS
a. Freedom from stains and foreign material on the shell of eggs must be
considered in assigning a quality designation to an individual egg. United States
Department Agriculture regulations describe three degrees of cleanliness: clean,
moderately stained, and dirty (figure 3-2). The following terms are descriptive of shell
(1) Clean--AA and A Quality. The shell of a clean egg is free from foreign
material and from stains or discolorations that are readily visible. An egg may be
considered clean if it has only very small specks or stains and if such specks or stains
are not of sufficient number or intensity to detract from the generally clean appearance
of the egg. Eggs that show traces of processing oil on the shell are considered clean
unless otherwise soiled.