On 3 Jun 2005 14:45:29 GMT, Dave Hinz wrote:

On Fri, 03 Jun 2005 04:41:45 GMT, Edward Greeley wrote:
OK, Jeff, I LOOKED at a jar of Hellman's "REAL" Mayonaise that is in my
fridge which bears a "Best if used by" date of Oct 11 05. The label
plainly, clearly and specifically states: "REFRIGERATE AFTER OPENING".

The list of ingredients includes WHOLE EGGS and EGG YOLKS. Ain't NO WAY
I would use the stuff if it had been stored at room temp for any length
of time (say, more than a couple of hours max) 'cause I've had food
poisoning before and it's not a lot of fun.

Are you familiar with what the canning process does, and why "before
opening" is different than "after opening" in this context?

I don't believe mayo is actually "canned", as in hermetically sealed
while sterile. All the mayo jars I recall had waxed paperboard inner
lids under the screw cap - hardly as effective as a metal hey - metal
content! lid with a rubber gasket. And I've never noticed any vacuum
"whoosh" upon opening mayo. (Not that vacuum is essential to a
hermetic seal, they could have cooled the Pasteurized mayo in a
sterile environment before sealing the jar, but one would expect to
find some pressure differential at least occasionally if the jars were
truly sealed.)

Loren