Only way to never lose is to borderline poison your coworkers. Most people are smart enough to not blatantly eat other people food that they prepared but if you leave a can of pop or unopened candy bar, it's pretty much open season.
Bring in some old expired shyt just once. Generally you'll weed out the motherfukkers quickly. "Who's expired creamer was in the fridge?"
Mine, why?
Thats gross, you need to throw your old shyt away.
I wasn't done with it. Therefore I didn't know it was expired, what were you doing with it anyway?
Oh....well I was used a little bit and my coffee tasted like shyt and when I smelled the creamer it was expired.
Well, that's what you get, had you asked me for some creamer I would have specifically told you not to use mine since it's getting close to the cutoff.
Just keep the fukking fridge clean....
Just bring your own fukking creamer.....