About 1 month
If eggs start out as Grade AA, they remain AA for only two weeks if properly refrigerated. After that, they'll be Grade A for another 2 weeks.
Eggs can remain edible for even longer than one month, but freshness (egg yolk that sits firm and high, and a thick viscous egg white) will be noticeably less after two weeks.
There is an expiration date on the carton. If in doubt, put the egg in water. If it floats, do not use it.
at 11:27 AM on Sep. 23, 2010