In article , aemeijers wrote:

Just adding nitrogen won't make much difference. You'd have to find some
way to suck out the normal-ratio air out at the same time, or there
would still be plenty of oxygen in there. Hence all the vacuum-baggie
food sealing machines. I find that manually deflating the zip-lock
baggie as I seal it (by careful folding and pushing) helps prolong the
time the food stays tolerable. Makes a big difference with cheese and
such. (Alright, I confess- I live alone, so I suck the last bit of air
out with my mouth, and dog down the zipper with my teeth.)

Works even better if you use a soda straw.