3-17. YOLK AND WHITE
Yolk and white are considered together, since the condition of one influences the
condition or grading of the other. For example, the firmer the white, the more difficult it
is to see the yolk outline (figure 3-5). The conditions that determine grade
classifications are as follows:
a. AA Quality. The white must be clear and firm so that the outline of the yolk is
only slightly defined when the egg is twirled before the candling light. The yolk must be
practically free from apparent defects.
b. A Quality. The white must be clear and at least reasonably firm, so that the
outline of the yolk is only fairly well defined when the egg is twirled before the candling
light. The yolk must be practically free from apparent defects.
c. B Quality. The white may be weak and watery so that the yolk outline is
plainly visible when the egg is twirled before the candling light. The yolk may appear
dark, enlarged, and flattened, and may show clearly visible germ development. It must
not show blood as a result of such development but may show other serious defects
that do not render the egg inedible. Small blood spots or meat spots, not over 1/8 inch
(3 mm) in diameter may be present.
3-18. BROKEN-OUT APPEARANCE (SETTING THE SIGHTS)
a. All the various quality factors are considered in combination when the
inspector decides to break out an egg. The inspector views several eggs before the
candling light, determines the egg quality, and then uses the egg break-out plate to
confirm the actual quality of one of the eggs. This procedure is called "setting the
sights." It provides feedback as to the egg inspector's proficiency in determining quality.
b. It is recommended that each inspection station secure and use the USDA
chart entitled "US Standards for Quality of Individual Shell Eggs." It clearly depicts, in
color, the actual quality grade to be assigned based on the plumpness of the yolk, the
amount and density of the thick white, and the condition of the shell.
c. The interior quality factors have been covered in this lesson. However, when
an egg is broken out, you will observe that the AA Quality egg covers a small area and
has a small amount of thin white, that the A Quality egg covers a moderate area and
has a medium amount of thin white, and that the B Quality egg covers a very wide area
and has a large amount of thin white thinly spread. See figure 3-6.