Lunch (and other food) thievery seems to be a rampant problem in many offices and other places with a communal fridge. You could use a thief-deterring, fake, mouldy sandwich bag, or lace your food with laxatives, but maybe there's a less extreme method. What's yours?
The food folks at Epicurious offer a few suggestions for combatting office lunch theft, but some of them seem inconvenient for us, such as making food that's disgusting.
One option is to bring a lunch bag with an ice pack and skip the fridge all together, but that doesn't help at home if your roommates help themselves to your food.
What would or did you do in these kinds of situations?