A funky smell . . .

Every so often we get this funky smell in our pantry and down our hallway.  It happened a few months back and I searched and smelled and searched and smelled and took everything out and looked some more.  I never found the culprit.  But the smell went away and I never thought about it again - until a few days ago.  It's back!  I believe this the the third time is has been back.  But it seems like there is a 6 month or so break in between.  Weird.  It is a really strong meaty garlicky smell.  It reminds me of a strong salami smell.  Salami that has been setting out for a day or two.  I have no idea what it is and it is diving me nuts!  I have smelled around and around and can not find the source!  Grrr......  Anyone have any ideas?  :)  Wanna come sniff my pantry?  I would love to lose the smell for good.  I promise I wouldn't mind.  But until then I have stocked up my febreeze air-fresheners and sprayed everything... it still smells!  It is so strong that nothing helps!  Yuck!