[blairbits]

IANAL or anything even remotely resembling one, but it seems to me that this could be begging for legal trouble if an employee was fired for this. I could be very wrong, but depending on how you go about this it has elements of entrapment, etc. all over it.

EDIT: Also seems like a very minor issue. I'm tempted to think that you're trolling. Perhaps this person wasn't aware it was someone else's? Really, I think a memo reminding everyone that their own food is their own should be enough to clear this up.

[bendauphinee]

I can vouch that this isn't a troll question. Having worked with him for a while, he's asking a good question about how best to keep his company family intact without making everyone feel like jerks about the whole thing.

[RyanIyengar]

"Person who takes lunch from the fridge" isn't a protected class as far as I know, and a lot of states are basically "at-will", which means you don't really need a reason to fire anybody at any time.

[samuellevy]

Knowing what it's like to work in a very small/close-knit company, simple notes/memos tend to come off as very passive-aggressive, and cause discord.