I usually travel solo and have not had a problem with bears.  Had a small one - the size of a Newfoundland dog - in camp Sept. 2010 but ran it off (I wanted to pet it but knew better).

Anyway, my dog serves as the smell-ability tester of my food pack.  He knows what goes in the Bear Vault because he smells it on the way in.  When it's loaded, I close it up and set it down.  He looks at it, gives it a single sniff, and turns away.  As soon as I open the lid, though, he's right there.

I do the same thing with the other food containers, which hold either low- or no-odor items, all packaged in Ziploc-type bags that don't transmit odors, such as those used for dog treats.

Bears' noses are supposedly much better than dogs' but until I find a better tester I'll continue to rely on my current method.

Also, I stash my food pack in a low spot, since odors sink at night.

Dave