Not always an urban legend.
There were five different DNA samples recovered from the mayonnaise in a McDonald's where I used to live...
(Mr._Pickles, Sun 11 Jan 2009, 1:15, 3 replies)

Oh do check your Snopes...
Stuff like that is impossible because the mayonnaise is always kept in a sealed container.
( jim_bob can herd cats., Sun 11 Jan 2009, 10:54, closed)

Then how do they get it out if it is sealed?
I know: unseal it...

If you saw the people that worked in that McDonald's you'd believe it too.
(Mr._Pickles, Sun 11 Jan 2009, 14:05, closed)

Go on
Where, precisely, do you think this would happen? In the kitchen bit - you know, the one directly behind the counters and visible to anyone ordering?

Or were people casually sauntering to the toilet with the mayonnaise dispenser?
(ubergeekian, Sun 11 Jan 2009, 21:14, closed)

For the love of Joseph
Why do people persistently lie/exaggerate about this sort of stuff? Do you really think that Bill Gates is going to send you money as well?
(powervator and NONE SHALL PASS, Sun 11 Jan 2009, 11:50, closed)

I wouldn't be ungrateful if he did give me some money,
but no, I don't hold out hope for it.

Also, see my above comment. I believe that it could have happened from what I saw at that 'restaurant'.
(Mr._Pickles, Sun 11 Jan 2009, 14:07, closed)

How exactly would they work out that there are 5 different DNA samples?
Just think about that one.
(littlenipple hate's bad grammar, Sun 11 Jan 2009, 21:45, closed)