frequently has a fruity odor. Various organisms have been associated with this rot,
including Citrobacter, Salmonella, and Alcaligenes.
c Sour Eggs. On candling, sour eggs show a weak white and murky shadow
around an off-center, swollen yolk. These eggs are also called fluorescent or
fluorescent green rot. A fluorescent green pigment throughout the albumen is produced
by Pseudomonas species.
d. Green Whites. Green whites of broken out shell eggs exhibit fluorescence
when observed with UV light. Shell eggs with green white may or may not have a sour
odor. This defect is caused mainly by Pseudomonas fluorescens.
e. Musty Eggs. These shell eggs appear clear and free from foreign material
when candled. The musty odor may be caused by odors in the atmosphere being
absorbed by the egg contents. Also, some microorganisms occasionally invade shell
eggs and produce a musty odor.
f. Moldy Eggs. Mold growth is visible as spots on the shell, in checked areas
of the shell, or inside the egg. The mold contamination of shell eggs seem to be due to
the reuse of moldy packing materials. Several molds, such as Penicillium, Alternaria,
and Rhizopus, can grow on shell eggs.
g. Red Rot. With red rot, the egg whites are stained red throughout and the
yolks are surrounded by custard-like material. An ammoniacal to putrid odor may occur.
Serratia marcescens is the usual cause of red rot.
h. Custard Rot. In this rot, the yolk is encrusted with custard-like material and
occasionally flecked with olive green pigment. The albumen becomes thin with an
orange tint. These shell eggs may have a slightly putrid to putrid odor. Citrobacter and
Proteus vulgaris have been associated with this type of spoilage.
i. Other Rots. Alcaligenes has been the organism causing both yellow rots and
green rots. These rots are similar in odor and in the appearance of albumen. However,
the yolk is dark yellow in yellow rot and dark green to black in green rots.
4-28. POTENTIAL HEALTH HAZARDS IN SHELL EGGS
A potential health hazard exists for all of the previously discussed deteriorative
conditions of shell eggs. Some of the microorganisms that may cause foodborne illness
due to shell eggs are as follows.
a. Salmonella species. Shell eggs and egg products are an important source
of Salmonella. However, pasteurization of egg products has eliminated this product as
a vehicle for this illness. Ice cream has been contaminated by infected shell eggs.