On Food and Cooking

Fertilized Eggs Despite folklore to the
contrary, there is no detectable nutritional
difference between unfertilized and fertilized
eggs. By the time a fertilized egg is laid, the
single germ cell has divided into tens of
thousands of cells, but its diameter has only
grown from 3.5 millimeters to 4.5, and any
biochemical changes are negligible.
Refrigerated storage prevents any further
growth or development. In the U.S. grading
system, any significant development of the
egg — from minute blood vessels (which
appear after two to three days of incubation)
to a recognizable embryo — is considered a
major defect, and automatically puts it in the
“inedible” category. Of course this is a
cultural judgment. In China and the
Philippines, for example, duck eggs
containing two- to three-week embryos are
boiled and eaten, in part for their supposed
contribution to virility. Because embryos
obtain some nourishment from the shell, these