This would be a lot harder to implement than a mere pleb such as the OP would think. Unless, you know, you wanted milk (which by the way was unpasteurized) to last the same amount of time as bread. Just about -every- piece of food would have a totally different decay time and it so would not make sense to give them all a week decay lifespan. Not to mention certain things that never expire, but merely dehydrate- such as various herbs and spices like taproot which can be eaten or used for string. And then there's food that -requires- a certain time frame in order to become somethings else. Grape juice > wine > vinegar is just one example I can think of.
I think that this is a horrible idea AT THE MOMENT. It doesn't mean it wouldn't be a good idea IN THE FUTURE.